Journal

Hong Kong J Radiol 2025 Jun;28(2):e80-90

 

 

Department of Diagnostic and Interventional Radiology, Kwong Wah Hospital, Hong Kong SAR, China

 

  Full Article in PDF

Magnetic resonance imaging (MRI) of the breast is an effective modality for screening high-risk patients, local staging and monitoring breast malignancies that are occult on radiography and sonography. This article summarises our centre’s experience in MRI-guided breast biopsy over the past 10 years, with the aim of reviewing the fundamentals of the procedure and emphasising tips and tricks for technically challenging cases.

 

MRI of the breast is performed for indications as categorised by the European Society of Breast Cancer Specialists working group, including screening for high-risk patients such as those with a strong family history of breast malignancies or known genetic mutations, e.g., BRCA1 and BRCA2; characterisation of inconclusive findings on mammography or ultrasound; assessment for unknown primary breast cancer; preoperative local staging and surgical planning in patients with biopsy-proven breast malignancy (particularly those considered for breast conserving therapy); and disease monitoring in known breast malignancies, e.g., evaluating treatment response to neoadjuvant chemotherapy.[1] When a suspicious lesion occult on conventional breast imaging (i.e., mammography and ultrasound) is detected on MRI, an MRI-guided biopsy should be performed if a targeted second-look ultrasound is unyielding according to the American College of Radiology (ACR)[2] and the European Society of Breast Imaging[3] recommendations. Absolute contraindications to MRI-guided breast biopsy are the same as for any MRI scan, including the presence of MRI-incompatible metallic or magnetic implants, claustrophobia, contrast allergy, or severe renal impairment.[4] Relative contraindications include thrombocytopenia and coagulopathies.[4]

 

At our centre, MRI-guided breast biopsy is performed using one of two 1.5-T MRI systems (Achieva XR; Philips Healthcare, Best, the Netherlands, and MAGNETOM Sola; Siemens Healthcare, Erlangen, Germany) with phased-array dedicated breast coils containing four or seven channels, respectively. The MRI protocol for biopsy differs from the usual diagnostic protocol by using breast coils with fewer channels and prioritising rapid image acquisition with sequences optimised for target localisation.[5] Our protocol consists of T1-weighted pre- and post-contrast sequences acquired in 1-mm section thickness. Gadoterate meglumine is the gadolinium-based contrast medium of choice, administered at the recommended dose of 0.2 mL/kg (or 0.1 mmol/kg) at a rate of 2 mL/s via a pump injector. Dynamic T1-weighted three-dimensional fat-saturated images are acquired, with the first set of post-contrast images obtained 1.5 to 2 minutes after injection, followed by a second set at a 25-second interval, and then at 1-minute intervals up to 4 minutes, as recommended by the ACR guidelines.[2] Subtraction of the unenhanced images is performed.

 

Optimal patient positioning is crucial for procedural success. The patient is positioned prone with cushion support for the head and neck, and a headset for noise cancellation. Arms are positioned overhead with padding at the sternum, abdomen, and legs for comfort and stability. The targeted breast is placed hanging freely and as deeply and centrally as possible in the dedicated breast coil with the nipple pointing directly downwards.[6] The operator should ensure there are no breast folds resulting from compression at the edge of the coil, as this leads to uneven fat saturation on MRI.[7]

 

Once the patient is optimally positioned, breast compression is performed using a grid paddle. Pre-contrast MRI is conducted to verify breast placement to ensure the target falls within the multichannel localisation grid.[6] A fiducial marker, either an MRI-visible fish oil capsule or a small plastic marker is affixed to skin of the breast within the grid square, close to, but not directly over, the anticipated location of the target. Contrast is administered and MRI images are acquired as per protocol. Post-processing subtraction images are generated to localise the target.

 

Following localisation, the biopsy tract is planned either manually or using the computer-assisted localisation software[4] [6] (syngo MR XA 51; Siemens, Erlangen, Germany) [Figure 1a]. In the manual approach, an MRI grid worksheet (Figure 1b) with two sets of views, namely, the patient view and the MRI view, is used to select the localisation grid channel and needle tunnel based on calculation of lesion coordinates. The patient view represents a 90° anti-clockwise rotation of the sagittal MRI image, as in reality the patient lies prone. The image section where the hypointense localisation grid contacts the skin surface is taken as the first section (Figure 1c). The number of sections from this point to the target is multiplied by section thickness to determine lesion depth. The thickness of the needle guidance cube block (2 cm) is then added for calculation of overall needle insertion depth. Distances between the fiducial marker and the target along the horizontal and vertical axes are also measured. It is important to verify correct laterality (i.e., left or right breast) and approach (i.e., lateral or medial) when selecting the worksheet as each is different; and to carefully translate the target from the MRI view to the patient view by turning anti-clockwise of the clock face or direction by 90° on the worksheet, as any mistake in these steps will result in inaccurate targeting. Alternatively, the computer localisation software automatically calculates lesion coordinates and indicates the specific square of the multichannel localisation grid, the tunnel within the needle guide cube block, and the required needle insertion depth for accurate targeting.[6]

 

Figure 1. (a) Lesion localisation using computer software. (b) Magnetic resonance imaging (MRI) grid worksheet used for biopsy planning in manual calculation with image view on the left and patient view on the right. Note that the target position is at the left lower corner (black star) in grid square B2 (black arrow) on the image view (left). On the patient view (right) there is a 90-degree rotation from the image view, hence the target is located at the right lower corner (black star) in grid square B2 (black arrow). After careful translation of the target position from image to patient view, the best suited needle insertion tunnel of the needle guidance cube block is selected, which in this case is the one in the right lower corner (black star indicated by black arrow in IV of patient view). (c) Pre-biopsy sagittal image shows the section where the hypointense localisation grid touches the breast surface. The MRI-visible obturator is inserted into the square of the grid where the biopsy trajectory is calculated (white arrow). (d) Target lesion (white arrow) on T1-weighted post-gadolinium subtraction axial image. (e) The obturator is confirmed to align with the target in (d) [white arrow]. (f) The vacuum-assisted biopsy needle is inserted into the lockable needle guidance cube block and held in place for sampling.

 

Following injection of local anaesthesia and skin incision at the expected needle position based on calculated lesion coordinates, a small lockable needle guidance cube block is inserted into the localisation grid channel (i.e., one of the many channels/boxes from the square grid; A1 to F8 in Figure 1a) over the skin incision and secured. The numerically labelled plastic introducer sheath, with its depth stop set to the calculated insertion depth, together with the inner non-ferrous metallic trocar, is inserted into one of the tunnels of the needle guidance cube block, which is best positioned over the skin incision, and the coaxial system is advanced to the calculated lesion depth. The metallic trocar is then replaced with an EnCor MRI-visible obturator (BD Inc, Franklin Lakes [NJ], US) and MRI images are acquired to confirm the alignment of the obturator with the target (Figure 1d and e). The obturator is then removed and the vacuum-assisted biopsy needle is inserted to the same calculated depth. The aperture of the biopsy needle is oriented to face in the direction of the lesion relative to the selected needle tunnel, a technique known as ‘directional sampling’.[7] Vacuum-assisted biopsy is then performed (Figure 1f) with the desired number of cuttings and the needle is removed. A post-biopsy MRI scan is acquired to confirm the correct site and adequate sampling of the target.

 

After sampling, an MRI-compatible biopsy marker is inserted via the biopsy tract through the introducer sheath and deployed at the biopsy site. Acquisition of post-marker insertion images is optional and not routinely performed, as haematoma or gas artefacts often obscures the marker.[8] All needles are removed and haemostasis is achieved by manual compression of the breast for at least 15 minutes.

 

Bleeding and haematoma formation at biopsy site are the most common complications.[9] Other complications include infection and muscle injury (i.e., injury to the pectoralis muscles). Rare complications include pneumothorax and injury to mediastinal structures, which only occur when biopsy is performed using a freehand approach without a localisation grid.[9]

 

Thirty-seven consecutive cases of MRI-guided vacuum-assisted breast biopsies performed between August 2012 and August 2023 in a single centre were retrospectively reviewed. Target lesions were localised using the Philips or Siemens 1.5-T MRI system with dedicated breast coils and an Invivo (Philips, Amsterdam, Netherlands) or Breast BI 7 Coil (Siemens, Höchberg, Germany) localisation device. Biopsies were performed using 10-gauge EnCor or 9-gauge Suros (Hologic, Marlborough [MA], US) needles. Imaging characteristics including size, morphology, and enhancement pattern were recorded. Histopathology of all biopsied lesions was obtained with subsequent management documented.

 

The mean age of patients was 51.6 years (range, 33-76). Technical success was achieved in 35 out of 37 cases (94.6%). In three cases, the original target was not visualised on pre-procedural MRI, resulting in cancellation of the procedure in two cases, while a nearby target was selected in the remaining case.

 

In 27 cases (77.1%), the lateral approach was adopted and the biopsied breast was placed in the ipsilateral coil. In eight cases (22.9%), the medial approach was used, and the breast was placed in the contralateral coil. A total of 34 lesions were biopsied using a 10-gauge EnCor needle and one lesion was biopsied using a 9-gauge Suros needle. Between 8 and 24 cuttings were taken for each target, with an average of 13 cuttings made. Three cases (8.6%) were complicated by biopsy-site haematomas: two were managed by prolonged manual compression for more than 30 minutes and one required aspiration of the haematoma using the vacuum-assisted biopsy device followed by manual compression. Haemostasis was successfully achieved in all three cases.

 

Table 1 shows the histology of the lesions and Table 2 shows the malignant diagnoses. Of the 11 malignant lesions, one case (9.1%) yielded a false-negative result from MRI-guided biopsy and proceeded to surgical excision after consensus was reached at the multidisciplinary meeting due to clinical and radiological-histopathological discordance. Histology from the surgical specimen revealed invasive ductal carcinoma (Table 2).

 

Table 1. Histopathological results of biopsied lesions (n = 35)

 

Table 2. Histopathological results of the biopsied lesions positive for malignancy (n = 11)

 

Six malignant lesions (54.5%) presented as non-mass enhancement and five as mass enhancement (45.5%). The size of the malignant lesions ranged from 0.5 cm to 4.3 cm. Four lesions (36.3%) showed restricted diffusion, while seven (63.6%) did not. Nine malignant lesions (81.8%) exhibited a type II enhancement curve and two (18.2%) demonstrated a type III enhancement curve. Ten malignant lesions (90.9%) were classified as BI-RADS (Breast Imaging Reporting and Data System)[10] category 4 and the remaining case (9.1%) as category 5. All but one patient underwent surgery with either mastectomy or breast conserving therapy; the remaining patient declined surgery and remained under regular clinical and radiological follow-up.

 

MRI-guided vacuum-assisted biopsy of the breast is a technically demanding procedure requiring specialised equipment and a skilled, well-trained team with appropriate experience. Various factors contribute to procedural success. First, patient safety in the MRI suite should be ensured for a smooth procedure. Any equipment entering the suite should be carefully examined for MRI compatibility.[2] A trolley is usually prepared for the transport of equipment in and out of the suite between image acquisition and biopsy, and all metallic devices must be removed during image acquisition. Second, efficiency is essential for successful biopsy owing to limited timeframe between lesion enhancement and contrast washout, while progressive background parenchymal enhancement further obscures targets.[7] It is also important to note that patients are often placed in an uncomfortable position and may move during prolonged procedures, resulting in lesion motion and therefore sampling failure.[7] Meticulous preprocedural planning with review of the diagnostic MRI, education and communication with the patient prior to biopsy to reduce anxiety and manage expectation, particularly regarding the importance to stay still throughout the procedure, and efficient execution of each biopsy step is therefore crucial to achieve procedural success. The following are tips and tricks accumulated over the years to address challenging cases.

 

Controlled compression of the breast with moderate pressure is performed with a grid paddle and should be adequate for immobilisation with the breast just taut. Inadequate compression increases the risk of mistargeting due to breast and lesion motion throughout the procedure, while excessive compression increases patient discomfort and may impede blood flow to the breast, resulting in reduced or non-enhancement of the target leading to localisation failure.[9]

 

Thin breasts (Figure 2a) present unique challenges. Target lesions may not fall adequately into the breast coil to allow needle access. Optimising patient positioning can markedly improve procedural success, whereby chest pads can be removed from the coil or replaced by thinner pads, and the patient can be tilted into an oblique position, allowing the breast to drop further into the coil lumen.[11] After compression, breast thickness is further reduced (Figure 2b) and may be inadequate to accommodate the standard biopsy needle, therefore compression may be reduced to increase tissue thickness to allow biopsy.[12] Local anaesthesia can also be injected either anterior or posterior to the target to increase distance between skin and the target to accommodate the biopsy needle. A blunt tip needle, half-aperture size needle or petit needle (e.g., 13-gauge) can be employed to minimise chest wall injury or contralateral skin penetration risks.[11]

 

Figure 2. Biopsy techniques in thin breasts. Thin breasts are commonly encountered in the Asian population and pose difficulty due to limited tissue thickness which may not adequately fall into the breast coil lumen. (a) A patient with thin breasts without compression on diagnostic magnetic resonance imaging. (b) Further reduction in breast thickness is noted after compression during biopsy in the same patient. A half-aperture size needle is employed in this case to avoid skin injury.

 

Occasionally, the target may fall onto the intersection of localisation grid squares after injection of local anaesthesia as shown in Figure 1a (red circle). In such cases, directional sampling and appropriate manoeuvring will significantly improve procedural success.[7] The needle guidance cube block is inserted into the A4 square and the biopsy needle is inserted into the tunnel of the cube block indicated by computer software (tunnel c3; highlighted in green), then directional sampling is performed with the aperture of the biopsy needle facing the 7 to 8 o’clock position aiming at the target, while manual pressure is applied by the operator’s finger through another grid square (B4 in this case) in attempts to push the breast tissue and hence the target towards the direction of the biopsy needle to aid sampling (Figure 1a). Niketa et al[11] also described a biopsy technique with two diagonally placed entry sites in adjacent holes paired with directional sampling technique to improve sampling success in such cases.

 

For anterior lesions, with large breasts, they may touch the table and distort the breast, rendering localisation difficult. Padding can be added to raise the body from the coil so that the target is more easily reached.

 

For lesions close to the chest wall (Figure 3a), removing coil cushion covers brings the chest closer to the coil aperture. The arms can be placed down by the sides of the patient instead of above the head, as this relaxes the pectoralis muscles and allows the breast to sink deeper into the coil (Figure 3b). However, if the target is too close to the pectoralis muscles, the arms should be placed above the head to help retract the muscle away from the coil lumen to avoid muscle injury, which can cause excessive pain and haemorrhage. Tilting the patient into an oblique position may also help the posterior parts of the breast sink further (Figure 3c). On rare occasions, the target may lie posterior to the localisation grid even after these manoeuvres. Performing the biopsy posterior to the grid or by freehand needle insertion without breast compression and localisation grids has been described.[11] The importance of maintaining stability of the needle position in these scenarios is emphasised, as the absence of support from the localisation grid and/or immobilisation of the breast from compression increases the difficulty of targeting.

 

Figure 3. Biopsy techniques for posteriorly located lesions. (a) A posteriorly located BI-RADS (Breast Imaging Reporting and Data System) category 4 lesion (arrow). (b) The patient’s arms are placed down by her sides to relax the pectoralis muscles, allowing the posterior breast to sink deeper into the coil. (c) The obturator (arrow) is aiming at the target lesion after patient positioning was optimised. Sampling was successful in this case.

 

It is difficult to target medial lesions from the medial side due to the increased distance between the biopsy apparatus and the breast when the breast is placed in an ipsilateral coil. The design of the breast coil, with a downward slant from the lateral bar to the sternal bar, also aggravates the difficulty of accessing posteromedial lesions, as the further the biopsy needle travels, the more anteriorly (towards the nipple) the needle tip will be directed due to this angulation.[6] It is thus often helpful to place the targeted breast in the contralateral breast coil (i.e., the right breast in the left breast coil [Figure 4]), which shortens the distance between the biopsy apparatus and the target and reduces the downward angulation the biopsy needle must overcome. This is a less comfortable position for the patient due to the tilting, making it harder to stay still. It is therefore vital for operators to optimise patient comfort before commencement of biopsy to minimise lesion motion. Another limitation to this manoeuvre is that obese patients may not be able to fit through the bore of the MRI.[6]

 

Figure 4. Biopsy techniques for medially located lesions. The patient was initially positioned with her right breast placed in the right breast coil. She had a target lesion located in the right inner breast (a) [arrow]. However, simulation for biopsy found that the target would be difficult to approach from the medial side as the large distance between the biopsy apparatus and the target rendered positioning of the biopsy needle (b) [arrow] suboptimal. The patient was then repositioned obliquely, with her right breast placed in the left breast coil (c). The biopsy was completed smoothly with successful sampling.

 

Injury to the skin is the primary concern in these lesions. If the needle aperture is not completely embedded within the breast during biopsy, air leakage and loss of vacuum effect may ensue, which further lower the rate of successful sampling.[11] This can be tackled by generous injection of local anaesthetic proximal to the target to increase tissue depth to accommodate the biopsy needle.[11] The biopsy needle can also be inserted a few millimetres beyond the target so that the target falls into the proximal part of the needle aperture. Alternatively, smaller-aperture needles may be employed.

 

Biopsy around the nipple-areolar complex carries increased risks of haemorrhage and pain as it is a highly vascularised and innervated structure. It also raises cosmetic concerns. In these cases, the nipple-areolar complex can be manually rolled away from the expected site of skin incision and biopsy needle entry to avoid injury to the complex.[11]

 

Breast implants are increasingly common, and their presence renders biopsy difficult. The operator must exercise extra caution not to puncture the capsule, which may result in implant rupture. Adequacy of breast parenchymal thickness should be assessed according to the expected biopsy trajectory and if there is inadequate tissue depth, half-aperture needles can be employed.[7] If the target is located too close to the implant, blunt-tip needles may minimise the risk of implant puncture (Figure 5), or alternatively, fine needle aspiration can be performed instead.[12] Injection of local anaesthetic between the target and the implant also allows tissue dissection and increases the distance between the two, providing more room for tissue sampling.

 

Figure 5. Biopsy techniques in patients with breast implants. A patient with breast implants and a BI-RADS (Breast Imaging Reporting and Data System) category 4A lesion in the right outer breast (a) [arrow]. The presence of breast implants often limits tissue depth for sampling, especially when the target is located close to the implant. This can be resolved by using needles with a blunt tip or half aperture, as in this case (b).

 

Non-visualisation of the target (Figure 6) in preprocedural MRI has been reported in approximately 8% to 13% of cases.[13] Several factors should be taken into consideration before abandoning biopsy. The diagnostic MRI should be carefully reviewed to identify the sequences in which the target is best visualised. For instance, the lesion may be T2-hyperintense or shows restricted diffusion on diffusion-weighted images (Figure 7), and if it is not well delineated in the standard pre-biopsy MRI sequences, these additional sequences should be performed. This is also helpful when other non-target lesions are conspicuous in these sequences and can be identified as landmarks. Sometimes, the lesion may not be identified due to inherent differences between the breast coils used in diagnostic and pre-biopsy protocols, as the latter includes a smaller number of channels, which may lower the image quality. It is also important to bear in mind that the breast is compressed using a grid paddle in preprocedural MRI, whereas no compression is applied during diagnostic MRI. Enhancement dynamics of the target may therefore differ as blood inflow may be impeded by compression of the breast, preventing lesion enhancement and resulting in a false-negative scan.[7] In such cases, the operator should verify that compression pressure is not excessive and reduce it if necessary. Another tip is to prolong post-contract image acquisition, e.g., at 1-minute intervals for up to 5 minutes, as lesion enhancement may be delayed due to compression of the breast.[6] Non-visualisation can persist after these manoeuvres due to several factors, including fluctuation in background parenchymal enhancement related to hormonal cycles and transient infective or inflammatory process.[7] In such events, the biopsy should be cancelled. However, non-visualisation of the target during biopsy does not preclude malignancy, which has been found in approximately 3.5% of such cases upon follow-up imaging.[14] It is therefore prudent to perform a follow-up MRI within 6 months upon cancellation of biopsy according to ACR recommendations.[2]

 

Figure 6. Non-visualisation of target in pre-biopsy magnetic resonance imaging (MRI). (a) Enhancing target in the left inner breast (arrow). (b) The target was not well delineated in the pre-biopsy MRI despite adjustment of compression pressure and acquisition of delayed post-contrast images; therefore, the biopsy was abandoned. A follow-up scan performed 7 months later also shows the lesion was no longer visualised (not shown).

 

Figure 7. Non-enhancing lesions with restricted diffusion. Diffusion-weighted imaging (DWI) [a, c] with corresponding apparent diffusion coefficient maps (b, d) showing a 1.6-cm irregular area of restricted diffusion in the left inner breast (arrows) without corresponding enhancement. This lesion was graded as BI-RADS (Breast Imaging Reporting and Data System) category 4A, and magnetic resonance imaging–guided biopsy was performed based on DWI images, without the standard T1-weighted pre- and post-gadolinium injection sequences. Histopathology revealed fibrocystic change with sclerosing adenosis and ductal ectasia (benign).

 

Manual compression is applied to the biopsied breast for haemostasis for at least 15 minutes. A pressure dressing or tight breast wraps can be used to facilitate further compression afterwards. A sizeable biopsy site haematoma may sometimes be seen on post-biopsy MRI. In such cases, the vacuum-assisted biopsy needle can be re-inserted through the co-axial system and switched to aspiration mode for evacuation of the haematoma before deployment of the biopsy marker (Figure 8). This often reduces pain as well as minimises the risk of marker displacement. In cases of uncontrolled bleeding with suspected arterial injury, thrombin injection into the biopsy cavity may be helpful for haemostasis control.[11]

 

Figure 8. Postprocedural haematoma. (a) A large biopsy site haematoma (arrow) on a postprocedural image. (b) Another case complicated by a biopsy site haematoma. A cavity with an air-blood level (arrow) is seen as a vertical line in this prone patient. (c) Aspiration of the haematoma was performed in the case shown in (b) with the vacuum-assisted biopsy device. Post-aspiration image shows marked reduction in the size of the cavity (arrow).

 

Unlike ultrasound-guided biopsy where there is real-time visualisation of the biopsy trajectory and lesion, or in stereotactic- or tomosynthesis-guided core biopsy where specimen radiographs confirms the presence of calcifications, there is no direct method to assess targeting accuracy in MRI-guided vacuum-assisted biopsy. Radiological-histopathological concordance is therefore of utmost importance to avoid missing any malignancies in cases of suspicious imaging findings with negative biopsy results.[15] [16] It is the operator’s responsibility to review the histology results and report any discordance to the surgical team, for which the next appropriate step of management entails a repeated or excisional biopsy.

 

MRI has become an indispensable component of breast imaging due to its high sensitivity in lesion detection. However, its limited specificity, with significant overlap of MRI characteristics between malignant and benign lesions, highlights the importance of radiological-histopathological correlation. It is therefore vital for breast radiologists to understand the fundamentals of MRI-guided vacuum-assisted biopsy in the face of its growing demands to achieve technical success and guide the management of breast lesions occult on mammography and ultrasound. MRI-guided vacuum-assisted biopsy of the breast is a safe, feasible, and effective procedure with high diagnostic yield in the hands of experienced interventionists.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hong Kong J Radiol 2025 Jun;28(2):e107-10 | Epub 19 June 2024

 

 

Department of Radiology, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China

 

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A 68-year-old Chinese woman presented to the Accident and Emergency Department of our institution in March 2023 with confusion, gait instability, and a history of falls. She had experienced a rapid decline in mobility and motivation, rendering her homebound since December 2022. Her medical history revealed repetitive behaviour spanning over a decade, alongside co-morbidities such as diabetes mellitus and mild anaemia since 2007. Neither the patient nor her relatives reported seizures or loss of consciousness. Physical examination showed no focal neurological deficits. Dementia evaluation by the Montreal Cognitive Assessment test yielded a score of 2 out of 30, indicating a high clinical suspicion.

 

Non-contrast computed tomography (CT) of the brain was unremarkable with known chronic ventriculomegaly as the only notable finding. Subsequent contrast-enhanced magnetic resonance imaging (MRI) showed extensive symmetrical blooming artefacts in various deep grey matter areas on the susceptibility-weighted imaging (SWI) sequence, including the bilateral caudate nuclei, lentiform nuclei, thalami, red nuclei, substantia nigra, and bilateral dentate nuclei of the cerebellum. Diffuse gyriform-like blooming artefacts were observed outlining the surfaces of the cerebrum and cerebellum (Figure 1). These MRI findings suggested significant mineral deposition, raising suspicion of aceruloplasminemia and other differential diagnoses such as other neurodegeneration with brain iron accumulation. In view of the suspected iron accumulation, contrast-enhanced CT of the abdomen and the pelvis, as well as MRI of the liver and the heart, were performed. The CT scan revealed diffuse hyperattenuation of the liver parenchyma, while MRI showed evidence of iron overload in both the liver parenchyma and myocardium (Table 1).

 

Figure 1. Brain magnetic resonance imaging (3T). Axial susceptibility-weighted sequence shows extensive symmetrical blooming artefacts in deep grey matter areas, including (a) bilateral caudate nuclei (yellow arrows), lentiform nuclei (white arrows), thalami (red stars); (b) red nuclei (yellow circles), substantia nigra (orange arrows); and (c) bilateral dentate nuclei of the cerebellum (red arrows). (d, e) Diffuse gyriform-like blooming artefacts outlining the surfaces of the cerebrum and cerebellum (yellow arrowheads).

 

Table 1. Calculated T2-star value of liver parenchyma and myocardium.

 

Biochemically, the patient exhibited a markedly low ceruloplasmin level of under 0.02 g/L (normal range = 0.22-0.58), an elevated ferritin level of 3270 pmol/L (normal range = 25-689), and a low iron saturation of 13.1% (Table 2). She also had a history of chronic mild anaemia for at least a decade, with haemoglobin levels ranging from 10.4 g/dL in April 2013 to 8.9 g/dL in March 2023. Genetic testing subsequently identified a pathogenic variant of the ceruloplasmin gene, confirming the diagnosis of aceruloplasminemia.

 

Table 2. Laboratory findings in our case.

 

The patient and her relative were counselled about the definitive diagnosis, and the features of the disease were explained. No specific treatment was prescribed for aceruloplasminemia due to chronic neurological symptoms and impaired cognitive function. The patient continued to receive holistic care in a residential elderly care home, with monitoring for her diabetes. Genetic testing was also offered to her first-degree relatives.

 

Aceruloplasminemia is a rare autosomal recessive disorder characterised by the absence or dysfunction of ceruloplasmin with consequent iron accumulation in various tissues and organs, leading to a spectrum of neurological and systemic manifestations.[1] Our case illustrates the importance of recognising the clinical and radiological features of aceruloplasminemia to facilitate accurate diagnosis and management.

 

Aceruloplasminemia was first documented in 1987 by Miyajima et al[2] in a 52-year-old woman with blepharospasm, retinal degeneration, and diabetes mellitus. The estimated prevalence is approximately 1 in 2,000,000 population among Japanese individuals born from non-consanguineous marriages.[3] Nonetheless, this estimation is region-specific and may not be applicable to other populations.[4] Clinical manifestations leading to diagnosis by neurologists include cerebellar signs such as dysarthria, trunk and limb ataxia, and involuntary movements including dystonia, chorea, and tremors. Symptoms may vary widely among individuals and may overlap with other neurological or metabolic disorders.[5]

 

To understand the pathophysiology of aceruloplasminemia, two distinct isoforms of ceruloplasmin are produced via alternative splicing in exons 19 and 20, resulting in a soluble form in plasma and a glycosylphosphatidylinositol-anchored membrane form.[6] The ferroxidase activity of the membrane-bound ceruloplasmin plays a vital role for incorporating ferric cation Fe³⁺ into plasma transferrin, facilitating its delivery to other cells via transferrin receptor 1. In the absence of ceruloplasmin, iron initially accumulates in astrocytes, triggering neuronal iron starvation. Consequently, neurons resort to alternative iron sources such as non–transferrin-bound iron, exacerbating toxicity (Figure 2).[1] [7]

 

Figure 2. The ferroxidase activity of the membrane-bound ceruloplasmin (CP) plays a vital role in incorporating ferric cation Fe³⁺ into plasma transferrin, facilitating its delivery to other cells. In the absence of CP, iron accumulates in astrocytes, triggering neuronal iron starvation. Consequently, neurons resort to alternative iron sources, such as non–transferrin-bound iron, exacerbating toxicity.1,7 Apotransferrin is the iron-free form of transferrin, indicating failure of iron incorporation. The accumulation of ferric cation Fe²⁺ also leads to fenton reaction with generation of highly reactive hydroxyl radicals, causing oxidative damage.

 

The hallmark radiological feature of aceruloplasminemia manifests as symmetric blooming artefacts on SWI, attributable to iron accumulation in the brain. Typically, this involves regions such as the basal ganglia and thalamus, cerebral cortex and dentate nuclei of the cerebellum.[8] Aceruloplasminemia stands out as the sole recognised disorder featuring both cerebral and systemic manifestations of iron accumulation.[9] As in our patient, cardiac and hepatic iron overload may also occur. Hepatic iron overload often presents with hyperattenuation of the liver parenchyma on CT scans and is quantitatively assessed via MRI dedicated to evaluating iron overload in the liver. Nonetheless, liver iron accumulation seldom leads to clinical manifestations such as cirrhosis or liver failure.[10] Iron deposition in other organs, including the heart, pancreas, and other endocrine glands, has been documented and can be evaluated by MRI.[7]

 

The neurological manifestations of aceruloplasminemia are heterogeneous and often progressive. In our patient, initial symptoms such as confusion, gait instability, and falls were consistent with those commonly reported in the literature. Documented neurological features included behavioural changes or psychiatric manifestations, cognitive impairment, extrapyramidal signs, cerebellar signs, and involuntary movements.[5] Another classic clinical manifestation is diabetes mellitus, typically presenting in the fourth to sixth decades of life in individuals without classic risk factors or need for insulin treatment.[11] The mechanism underlying the development of diabetes mellitus in aceruloplasminemia remains poorly understood, although iron accumulation is noted predominantly in exocrine rather than endocrine pancreatic cells.[12] Some studies suggest that the clinical triad of aceruloplasminemia may comprise neurodegeneration, diabetes mellitus, and retinal degeneration.[13] [14] Nonetheless retinopathy is less frequently observed in non-Japanese case series, and its direct association with aceruloplasminemia remains uncertain.[13] [14]

 

Biochemically, the first detectable parameters of aceruloplasminemia, as indicated by all major case series including our own, encompass mild microcytic anaemia, low transferrin saturation, and hyperserotonaemia. This biochemical triad holds crucial diagnostic significance long before other clinical manifestations emerge. Serum ceruloplasmin is typically undetectable or markedly reduced and serves as an important diagnostic parameter. Although mild microcytic anaemia often emerges as the earliest biochemical sign of aceruloplasminemia,[5] [10] it rarely leads to diagnosis at the early pre-symptomatic stage. By integrating biochemical studies with radiological and clinical manifestations, the exclusion of other differential neurodegenerative diseases becomes more manageable. As in our case, genetic testing provides definitive evidence to confirm the diagnosis of aceruloplasminemia and enables genetic counselling and family screening for at-risk individuals.

 

Treatment of aceruloplasminemia primarily involves iron-chelating agents; however, their effectiveness in reducing brain iron and alleviating neurological symptoms remains uncertain. Currently, there is no convincing evidence supporting the clinical benefits of iron removal therapy. Phlebotomy, another treatment option, is also considered suboptimal. Alternative strategies focus on preventing oxidative tissue damage, such as administering vitamin E or zinc sulphate.[10] Timely diagnosis and treatment are paramount to prevent irreversible neurological complications.[7]

 

Aceruloplasminemia is difficult to diagnose and requires a high level of awareness of its clinical features, biochemical parameters, and radiological findings. The biochemical triad of mild anaemia, low transferrin saturation, and hyperserotonaemia serves as a key diagnostic indicator when no alternative explanation is evident. The condition should be considered in patients who present with mild microcytic anaemia, early-onset diabetes mellitus, and unexplained liver iron overload. In later stages, adult-onset neurological dysfunction, such as behavioural changes, psychiatric disturbances, as well as cerebellar and extrapyramidal signs, become apparent. Corresponding MRI findings often reveal symmetrical hypointensity in the basal ganglia and thalamus, cerebral cortex and dentate nuclei of cerebellum in T2 and T2-star sequences, along with a pronounced blooming artifact in SWI. Prompt diagnosis is crucial to prevent irreversible neurological complications.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hong Kong J Radiol 2025 Jun;28(2):e111-27 | Epub 17 June 2025

 

 

Department of Radiology, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China

 

  Full Article in PDF

The clavicle, the acromioclavicular (AC) joint and the sternoclavicular joint can be affected by a wide range of pathologies, including infection, inflammation, degeneration, metabolic disorders, neoplasms, trauma, and congenital anomalies. This pictorial essay illustrates the radiological features of clavicular pathologies to facilitate accurate diagnosis and management, based on cases of clavicular, AC and sternoclavicular pathologies diagnosed in the Hong Kong East Cluster from April 2014 to April 2023.

 

A basic understanding of the anatomy of the clavicle and its articulations is essential for image interpretation. The clavicle is a horizontally oriented S-shaped bone that has a large medial metaphysis articulating with the sternum, a tubular diaphysis, and a flared lateral metaphysis that articulates with the acromion (Figure 1). The sternoclavicular joint is a synovial joint formed by the medial clavicular metaphysis, the clavicular notch of the manubrium sterni, and the cartilage of the first rib. The articular surfaces of the clavicle and manubrium are separated by a fibrocartilaginous disk.[1] The costoclavicular and sternoclavicular ligaments (thickenings of the joint capsule), and interclavicular ligament (located between the superomedial ends of the two clavicles) provide joint stability (Figure 2).[2] The AC joint is a planar diarthrodial joint located between the lateral surface of the clavicle and the medial surface of the acromion. Stabilisers of the joint include the AC joint capsule and the AC, coracoacromial, and coracoclavicular (consisting of trapezoid and conoid ligaments) ligaments. A flexible fibrocartilaginous disk is peripherally continuous with the joint capsule (Figure 3).[3] There are four types of acromion shape, namely, flat, curved, hooked, and convex. An unfused acromial ossification centre (os acromiale) is an anatomical variant.

 

Figure 1. Anatomy of the clavicle. (a) Axial-oblique T1-weighted and (b) short-tau inversion recovery magnetic resonance images of the right clavicle demonstrate the S-shaped bone with a large medial end, a tubular mid-portion, and flaring of the lateral end.

 

Figure 2. Anatomy of the sternoclavicular joint. (a) Coronal T1-weighted and (b) short-tau inversion recovery magnetic resonance imaging (MRI) of the right sternoclavicular joint with intact fibrocartilaginous disk (open arrows) and costoclavicular ligament (circle in [b]). (c) Coronal T1-weighted MRI of bilateral sternoclavicular joints shows the interclavicular ligament across the upper sternum (arrows).

 

Figure 3. Anatomy of the acromioclavicular joint. (a) Coronal proton density (PD)–weighted and (b) T2-weighted fat-suppressed magnetic resonance imaging (MRI) of the right acromioclavicular joint with normal acromioclavicular joint capsule (circles), which cannot be differentiated from the acromioclavicular ligaments on routine MRI. (c, d) Coronal PD-weighted MRI of the right shoulder demonstrates ligaments around the distal clavicle. The coracoacromial ligament is located most laterally (arrow in [c]). The trapezoid portion of the coracoclavicular ligament is located more medially and inserts onto the inferior margin of the lateral clavicle; the conoid portion (curved arrow in [d]) is the most medial and vertically oriented.

 

Cleidocranial dysostosis is a rare autosomal dominant disease that mainly affects midline skeletal structures, with features including hypoplasia or aplasia of the clavicles, large fontanelles, multiple Wormian bones, a widened pubic symphysis, and supernumerary teeth (Figure 4). Eight cases of cleidocranial dysostosis were identified during the review period.

 

Figure 4. A case of cleidocranial dysostosis. (a) Chest X-ray demonstrates aplasia of bilateral clavicles (ellipse). (b) Pelvic X-ray demonstrates widening of pubic symphysis (arrowheads). Frontal (c) and lateral (d) skull X-rays demonstrate widened sagittal suture (open arrows in [c]) and multiple Wormian bones (arrows in [d]). (e) Orthopantomogram demonstrates supernumerary teeth.

 

Septic arthritis of the sternoclavicular joint is uncommon and is usually monoarticular with an insidious onset.[4] Radiological features on radiographs and computed tomography (CT) include subarticular erosions, joint space widening, and fluid collections. Magnetic resonance imaging (MRI) features include bone marrow oedema, bone destruction, joint effusion, and inflammatory changes of the surrounding soft tissue. Both CT and MRI are useful for early diagnosis and assessment of complications such as associated osteomyelitis and retrosternal/chest wall abscesses that may require surgical treatment.

 

Spondyloarthropathies such as ankylosing spondylitis and psoriasis can affect the sternoclavicular joint. Radiographic and CT features include bone erosions, partial or complete fusion of the joint, and hyperostosis surrounding the joint[2] (Figures 5, 6 and 7). Rheumatoid arthritis may be accompanied by pannus formation with bony erosions on imaging.

 

Figure 5. Two cases of spondyloarthropathy of the sternoclavicular joint. (a-c) First case. (a) Coronal and (b) axial computed tomography (CT) bone window images of bilateral sternoclavicular joints in a patient with known ankylosing spondylitis. The right sternoclavicular joint demonstrates osseous fusion (circles), while the left shows hyperostosis with mild bone erosions and subchondral sclerotic changes (arrows). (c) X-ray of the cervical spine demonstrates bamboo spine. (d-f) Second case. (d) Coronal and (e) axial-oblique CT bone window images of the left sternoclavicular joint demonstrate hypertrophic change, bone erosions and sclerosis (open arrows) in a case of known psoriasis. (f) Pelvic X-ray demonstrates bony ankylosis of bilateral sacroiliac joints (arrowheads).

 

Figure 6. Two cases of the SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. (a, b) First case. (a) Radiograph of the clavicles demonstrates prominent hyperostosis in both sternoclavicular joints (circle), more on the right, and sclerosis in both distal clavicles (arrows). (b) Bone scintigraphy demonstrates diffusely increased tracer uptake in both sternocostoclavicular junctions and medial clavicular ends (open arrows), associated with hyperostosis, compatible with the ‘bull’s head’ sign. (c-e) Second case. (c) X-ray demonstrates hyperostosis of both medial clavicles (circle). A Ryles tube is noted (arrowheads). (d) Coronal and (e) axial bone window computed tomography images demonstrate corresponding significant sternoclavicular hyperostosis (open arrows in [e]), marked joint space narrowing on the right with cortical irregularities (arrowheads in [d]) and complete ankylosis on the left (arrows in [d]).

 

Figure 7. A case of osteoarthritis of the right acromioclavicular joint. (a) Radiograph and (b) coronal bone window computed tomography of the acromioclavicular joint demonstrate osteoarthritis with joint space narrowing, marginal osteophytes, subchondral sclerosis and cysts (circles). (c) Coronal short-tau inversion recovery magnetic resonance imaging (MRI) of the acromioclavicular joint shows subchondral bone marrow oedema (arrowhead) and thickened superior capsule (arrows). (d) Sagittal T1-weighted MRI shows inferior osteophyte of the acromion (open arrow) and capsular hypertrophy (curved arrows) of the acromioclavicular joint mildly indenting the supraspinatus tendon.

 

The SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome is an inflammatory condition with aseptic osteoarticular involvement and characteristic skin lesions. In adults, it usually involves the anterior chest wall (60%-95%), particularly the sternocostoclavicular junction, followed by the axial skeleton, such as the spine and sacroiliac joints. Features of SAPHO on radiographs and CT include bony sclerosis, cortical thickening, and narrowing of the medullary canal. Adjacent changes include joint space narrowing and periarticular osteopenia, as well as ligamentous ossification with bony bridging across the joint. CT is good for detecting the osteoarticular manifestations, while MRI is sensitive in detecting early disease with bone and soft tissue oedema. On bone scintigraphy, SAPHO in the anterior chest wall typically manifests as the ‘bull’s head’ sign, with mostly symmetrical increased uptake in the sternoclavicular regions.[5] The radiological differential diagnosis includes sternoclavicular osteoarthritis, condensing osteitis of the clavicle, osteonecrosis, and septic arthritis (Figure 6). Six cases of SAPHO were identified during the review period.

 

Osteoarthritis is a common cause of pain at the AC and sternoclavicular joints (Figures 7, 8 and 9). Radiological features include narrowing of the joint space, marginal osteophytes, capsular hypertrophy, subchondral sclerosis, cysts, and bone marrow oedema.

 

Figure 8. Two cases of complete chronic supraspinatus tear with geyser sign. (a-d) First case. (a) Radiograph shows a soft tissue shadow (arrows) above the acromioclavicular joint with mild osteoarthritic change. Superior migration of the humeral head and subacromial acetabularisation are noted, highly suggestive of chronic supraspinatus tear. (b) Transverse ultrasound demonstrates a cystic lesion with low-level echoes above the acromioclavicular joint (white star). Corresponding coronal (c) and sagittal (d) T2-weighted fat-supressed magnetic resonance images show complete supraspinatus tendon tear (open arrows in [c]) with uncovering and superior migration of the humeral head, disrupted inferior capsule (circle in [c]), and a well-defined homogenous cystic lesion resembling the geyser sign (black stars). Incidental findings include a subcortical bone cyst (arrowhead in [c]) and enchondroma (curved arrow in [d]) at the humeral head. (e, f) Second case. (e) Axial and (f) coronal T1-weighted fat-supressed volumetric interpolated breath-hold examination magnetic resonance arthrogram images of the right shoulder demonstrate a full-thickness tear of the supraspinatus-infraspinatus interdigitation (circle in [f]) with superior migration of the humeral head. There is contrast extension via the subacromial subdeltoid bursa to the acromioclavicular joint (arrows).

 

Figure 9. Two cases of sternoclavicular joint osteoarthritis. (a) First case. Coronal bone window computed tomography of bilateral sternoclavicular joints demonstrates osteoarthritis of the left sternoclavicular joint with joint space narrowing, articular irregularity, subchondral sclerosis and cysts (circle). The right sternoclavicular joint is preserved. (b, c) Second case. (b) Axial T2-weighted fat-supressed and (c) coronal T1-weighted magnetic resonance images of the left sternoclavicular joint demonstrate capsular thickening (arrows in [b]) and marginal osteophytes (arrowhead in [c]).

 

A chronic large full-thickness supraspinatus tendon tear can lead to superior migration of the humeral head, which may erode the subacromial-subdeltoid bursa and inferior AC capsule, forming a communication between the glenohumeral and AC joints. This may lead to a sizeable fluid pouch over the AC joint, giving rise to the geyser sign (Figure 8). During the review period, six such cases were identified.

 

Clavicular fractures (Figures 10, 11 and 12) are common and represent 2.6% to 5% of all fractures, with the vast majority occurring in the mid clavicle (69%-82%).[6] Apart from location, alignment of the clavicle with the AC and sternoclavicular joints should be assessed, since malalignment may signify significant ligamentous injury.

 

Figure 10. A case of right midclavicular fracture. (a) Coronal T1-weighted and (b) short-tau inversion recovery (STIR) magnetic resonance images demonstrate displaced midclavicular fracture (circles). T1-weighted hypointense, STIR hyperintense bone marrow change next to the fracture indicate posttraumatic change. (c) Coronal and (d) axial bone window computed tomography images show displaced midclavicular fracture (circles) with superior angulation and inferior displacement of the distal fragment.

 

Figure 11. Two cases of acromioclavicular joint injury. (a-d) First case. (a) Radiograph of the left acromioclavicular joint demonstrates slight superior displacement of the clavicle (arrows). (b-d) Sagittal and coronal T2-weighted fat-suppressed magnetic resonance imaging (MRI) of the left shoulder demonstrates increased signal in the coracoclavicular ligament (circle) and acromioclavicular ligament/joint capsule (open arrows), suggestive of Rockwood type II left acromioclavicular joint injury. (e-g) Second case. (e, f) Radiographs of the right acromioclavicular joint show markedly elevated clavicle with increased coracoclavicular distance, consistent with Rockwood type V right acromioclavicular joint injury. (g) Post–open reduction radiograph shows satisfactory joint alignment.

 

Figure 12. A case of posttraumatic left distal clavicle osteolysis. (a) Radiograph shows widening of the acromioclavicular joint with erosions at the lateral end of the clavicle (arrows). (b) Coronal and (c) axial bone window computed tomography demonstrates erosions over the lateral end of the clavicle (open arrows) with tiny adjacent osseous foci, and widening of the acromioclavicular joint with mild soft tissue swelling.

 

AC joint injury is a common injury, occurring in 9% to 12% of shoulder injuries. The Rockwood classification is the most widely used classification system for AC joint injuries. It is classified into six types, depending on the direction and degree of clavicular displacement, which correlates with the severity of injury and involvement of the AC and coracoclavicular ligaments, and the deltotrapezial complex (Table).

 

Table. Rockwood classification.

 

Sternoclavicular joint dislocations are classified as anterior or posterior, and posterior dislocation has potentially serious complications due to the risk of injury to mediastinal structures such as the trachea and great vessels. On non-rotated radiographs, a difference in the relative craniocaudal positions of the medial clavicles exceeding 50% of the width of the clavicular heads suggests dislocation. However, diagnosis by radiographs may be difficult due to anatomical superimposition. CT is required for definitive diagnosis and to assess potential mediastinal injury.

 

Distal clavicle osteolysis (Figure 13) is painful bone resorption of the distal clavicle, most common in young adults with male predominance. It can be categorised into posttraumatic or overuse forms, which share identical imaging findings. Radiological features on radiographs and CT include cortical irregularity, ‘flame-shaped’ bony resorption, and subchondral cysts involving the distal clavicle. MRI is most sensitive in demonstrating clavicular marrow oedema in the early phase of the disease. Effusion and capsular oedema are other features on MRI.

 

Figure 13. Posttraumatic right distal clavicle osteolysis. (a) Radiograph shows Rockwood type II injury with bone resorption at the inferior clavicular end (arrows). (b) Coronal proton density–weighted, (c) short-tau inversion recovery (STIR), and (d) sagittal STIR magnetic resonance images show widened joint space (double-head arrow in [b]) with capsular thickening (open arrows in [c]), and bone marrow oedema over the distal clavicle (circle in [d]).

 

The differential diagnoses of distal clavicle erosion include rheumatoid arthritis, hyperparathyroidism, and scleroderma.

 

Radiological features of clavicular osteomyelitis on radiographs and CT include cortical erosion, regional osteopenia, periosteal reaction, and adjacent soft tissue swelling (Figures 14, 15 and 16). On MRI, features of osteomyelitis typically include bone marrow oedema and surrounding soft tissue inflammatory change or collection. With time, an intraosseous abscess may form, typically seen as a focal intramedullary T2-weighted hyperintensity with variable rim enhancement. Subsequently, other osteomyelitic features such as sequestrum, involucrum, and cloaca formation may also become apparent.

 

Figure 14. A case of septic arthritis of the left sternoclavicular joint. (a) Coronal T1-weighted, (b) short-tau inversion recovery, (c) coronal, and (d) axial post-contrast T1-weighted fat-supressed magnetic resonance images show enhancing soft tissues (open arrows in [c] and [d]), bone marrow oedema of the medial clavicle and adjacent manubrium (arrowheads in [b]), and bony erosion of the medial end of the clavicle (arrows in [a]).

 

Figure 15. A case of Staphylococcus aureus septic arthritis of the right sternoclavicular joint. (a, b) Ultrasound shows gross capsular thickening of the joint (arrows in [a]) with cortical erosion over the articular surface of the clavicular head (arrowhead in [b]). (c) Axial soft tissue window and (d) coronal bone window computed tomography demonstrates enhancing soft tissue and fluid (open arrows in [c]) with subarticular erosions of the medial clavicle and adjacent manubrium (curved arrows in [d]). (e, f) Gallium-67 single-photon emission computed tomography/computed tomography of the thorax shows increased gallium activity involving the right sternoclavicular joint, adjacent right upper chest wall muscles with probable extension into the right medial clavicular head (circles).

 

Figure 16. A case of tuberculous osteomyelitis of the left clavicle. (a) Coronal and (b) axial soft tissue window computed tomography (CT) images demonstrate a lytic lesion at the clavicular head with cortical destruction (circle in [a]) and adjacent soft tissue swelling (arrows in [b]). (c) Axial T1-weighted, (d) short-tau inversion recovery (STIR), (e) axial, and (f) coronal post-contrast T1-weighted fat-supressed magnetic resonance images demonstrate a corresponding intramedullary T1-weighted hypointense, STIR hyperintense lesion with peripheral enhancement at the clavicular head (open arrows), and adjacent subcutaneous soft tissue oedema and rim-enhancing collection (curved arrow in [e]). (g) CT-guided biopsy confirms mycobacterial infection.

 

Bone tumours of the clavicle are rare, with a reported frequency of less than 1% of all bone tumours.[6] While primary bone tumour of the clavicle is uncommon, the majority are malignant and include plasmacytoma, osteosarcoma, and Ewing’s sarcoma (Figures 17, 18 and 19). Bone metastases can involve the clavicle, with breast, lung, and prostate cancer being the more common primaries. Radiological features of aggressive bone tumours on radiographs and CT include a wide zone of transition, cortical destruction, and periosteal reaction. On MRI, there is invariably marrow replacement, sometimes with bony destruction, extraosseous extension, and perilesional oedema.

 

Figure 17. Carcinosarcoma of the right clavicle in a patient with breast cancer post-radiotherapy. (a) Coronal T1-weighted, (b) short-tau inversion recovery, (c) coronal, and (d) axial post-contrast T1-weighted fat-supressed magnetic resonance imaging demonstrates a huge irregular heterogeneous enhancing T1-weighted isointense, T2-weighted hyperintense mass replacing the clavicle (arrows), with internal cystic components. (e) Ultrasound-guided biopsy confirms carcinosarcoma.

 

Figure 18. A case of myeloma at the left clavicle. (a) X-ray of the clavicle demonstrates a lytic lesion at the medial clavicle (circle). (b) Coronal T1-weighted, (c) short-tau inversion recovery (STIR), and (d) post-contrast T1-weighted fat-supressed magnetic resonance images demonstrate a corresponding T1-weighted intermediate, STIR hyperintense and enhancing nodular lesion (arrows), expansile with mild adjacent soft tissue oedema and enhancement. Small joint effusion and capsule enhancement are noted (open arrows in [c] and [d]). Myeloma was confirmed by bone marrow aspiration.

 

Figure 19. Two cases of bone metastases to the clavicle. (a-d) First case. (a) Radiograph of the left clavicle demonstrates an expansile destructive lytic lesion at the clavicular head with indistinct superior cortex (circle). (b) Axial soft tissue window computed tomography demonstrates a suspicious irregular hypoenhancing lung lesion in the lingula (open arrow), subsequently diagnosed as epidermal growth factor receptor mutation–positive lung carcinoma. (c) Axial bone window computed tomography (CT) and (d) positron emission tomography/CT demonstrate an expansile destructive lesion in the left clavicular head with pathological fracture and increased ¹⁸F-fluorodeoxyglucose uptake (arrows), compatible with bone metastasis. The right clavicular head is unremarkable. (e-g) Second case. (e, f) Axial bone window CT of bilateral clavicles of a patient with known prostate cancer demonstrate sclerotic lesions in the distal clavicle diaphyses (arrowheads). (g) Bone scan demonstrates innumerable foci of increased uptake, including the corresponding distal clavicles (circles), indicating disseminated bone metastasis.

 

The clavicle, AC joint, and sternoclavicular joint are important structures of the upper extremity. To make an accurate diagnosis for treatment guidance, radiologists need to be familiar with the normal anatomy as well as the radiological features of abnormalities across different imaging modalities.

 

 

 

 

 

 

 

 

Hong Kong J Radiol 2025 Jun;28(2):e141-53 | Epub 16 June 2025

 

 

Department of Diagnostic and Interventional Radiology, Kowloon West Cluster, Hong Kong SAR, China

 

  Full Article in PDF

Breast lesions can present as palpable lumps in children and young adults, causing anxiety to patients and their caregivers. Although malignant lesions are exceedingly rare in this age-group, familiarity with the spectrum of breast lesions and the diagnostic approach is crucial to guide appropriate management. Evaluation and intervention should be tailored to minimise damage to developing breast tissue. All patients with breast abnormalities should first undergo clinical assessment.[1] When imaging is indicated, ultrasound (US) is recommended as the initial radiological examination for females under 30 years of age with palpable breast masses, according to the American College of Radiology (ACR) Appropriateness Criteria.[2] Mammography is less favoured due to the ionising radiation and reduced sensitivity in dense breast tissues of young patients. Most benign lesions in young women are not visible on mammography.[2] [3] Digital breast tomosynthesis potentially increases lesion detection in overlapping tissue in young dense breasts. Magnetic resonance imaging (MRI) is used for defining disease extent, surgical planning, and screening in high-risk females with hereditary predispositions and prior irradiation.[1] [4]

 

This pictorial essay showcases both benign and malignant breast lesions in individuals under 30 years of age on multimodality imaging, with emphasis on various MRI presentations as its use in both diagnostic and screening indications has been rapidly expanding. Guidelines on screening and risk factors for early-onset breast cancer, including hereditary predispositions and prior radiotherapy, are included. The role of radiologists in follow-up imaging and the appropriate timing for image-guided intervention, while staying aware of the risks of iatrogenic injury to developing breasts, is discussed.

 

Breast development occurs at prenatal and pubertal stages. At the fourth week of gestation, paired ectodermal thickenings develop on the ventral surface of the embryo and extend in a line between the axilla and inguinal regions, forming the mammary crest. This is followed by involution of the mammary crest at the tenth week of gestation except at the fourth intercostal spaces, giving rise to breast buds.[3] [5]

 

Accessory breast tissue, also known as polymastia, develops when there is incomplete regression. This can be found in up to 6% of the population, usually occurring along the mammary crest and most commonly in the axilla.[1] Imaging shows heterogeneous fibroglandular tissue with characteristics similar to normal breast parenchyma[3] [6] (Figure 1). It is crucial to recognise this variant as it could be affected by the pathological processes that occur in normal breast tissues.

 

Figure 1. A 21-year-old female presented with a painful left axillary nodule. (a) Targeted ultrasound (US) shows a heterogeneous hyperechoic lesion at the left axilla similar to glandular breast tissue. (b-d) Magnetic resonance imaging (MRI) was subsequently performed as the US findings did not account for the clinical symptoms of significant pain. Axial T1-weighted (b), T2-weighted (c), and post-contrast T1-weighted MRI (d) of the left axilla showed a subcutaneous lesion with tissue signal identical to the left breast glandular tissue on all phases (arrows), consistent with accessory breast tissue.

 

Up to 70% of newborns experience physiological breast development under maternal oestrogen influence.[3] It can be unilateral or more commonly bilateral. This condition is transient and usually resolves spontaneously by 6 months of age. Normal breast buds may fluctuate in size and remain palpable up to 2 years of age, after which they remain quiescent until puberty.[3] US features include retroareolar hypoechoic tissue (Figure 2), or hyperechoic nodule with hypoechoic linear structures representing simple branch ducts.

 

Figure 2. A 7-month-old female infant with palpable right breast mass. (a) Right breast. (b) Left breast. Ultrasound shows asymmetrical hypoechoic tissues in both retroareolar regions, more prominent on the right. There was spontaneous resolution at follow-up, consistent with physiological breast development.

 

During puberty, female breasts develop under the influence of the secretion of oestrogen and other hormones. This is known as thelarche, which is divided into five stages on the Tanner scale[5] [7] (Figure 3). On US, stage I shows ill-defined echogenic retroareolar tissue. In stage II, a central stellate hypoechoic area appears. Stage III shows central spider-like hypoechoic projections extending out from the retroareolar region, with surrounding hyperechoic glandular tissue. Stage IV involves growth of periareolar hyperechoic fibroglandular tissue with a hypoechoic central area. Finally, stage V reveals hyperechoic fibroglandular tissue and increased subcutaneous adipose tissue with disappearance of the central hypoechoic area.

 

Figure 3. Ultrasound features of Tanner stages of normal breast development. (a) Stage I: Ill-defined echogenic retroareolar tissue. (b) Stage II: Echogenic retroareolar tissue with central stellate hypoechoic area. (c) Stage III: Central spider-like hypoechoic projections extending away from the retroareolar region, with surrounding hyperechoic glandular tissue. (d) Stage IV: The retroareolar hypoechoic central area persists, with enlargement of the periareolar hyperechoic fibroglandular tissue. (e) Stage V: Mature breast appearance with hyperechoic fibroglandular tissue and increased subcutaneous adipose tissue. The central hypoechoic area is absent.

 

Premature thelarche refers to isolated early breast development in girls under 8 years without associated skeletal maturation.[5] It can be unilateral or bilateral, symmetrical or asymmetrical. Imaging features are identical to thelarche, seen as developing breast tissue without discrete lesion on US.[8]

 

Gynaecomastia refers to enlargement of male breast tissue, occurring most frequently during adolescence due to physiological transient increase in oestrogen levels. It typically involutes spontaneously when androgen levels rise.[3] Secondary causes include Klinefelter syndrome; drug use (e.g., anabolic steroids, exogenous oestrogens, marijuana); and tumours such as prolactinomas.[3] [5] On mammography, a flame-shaped retroareolar density is characteristic, while it is triangular and hypoechoic on US (Figure 4).[3]

 

Figure 4. A 17-year-old male presented with a 3-month history of progressively enlarging bilateral chest wall masses. (a) Right breast. (b) Left breast. Ultrasound (US) showed triangular hypoechoic areas in the subareolar region of both breasts without increased vascularity on Doppler US (arrows), consistent with gynaecomastia.

 

Haematomas should be considered in patients who present with a new-onset breast lesion after recent trauma or surgery. They can be solid, cystic, or of mixed echogenicity on US, and are commonly avascular[1] [3] (Figure 5). It is crucial to look for the presence of foreign bodies, as removal may be needed.[3]

 

Figure 5. A 6-year-old girl presented with a right anterior chest wall mass after a fall injury. (a) Ultrasound (US) shows a lobulated echogenic lesion with cystic areas (arrow) beneath the right pectoralis major and minor muscles, superficial to the ribcage. (b) Colour Doppler US shows no increased vascularity. Follow-up US (not shown) shows complete resolution of the mass, consistent with haematoma.

 

Prior breast trauma can also result in fat necrosis, which may appear as solid masses to oil cysts, depending on lesion age.[3] [5] On US, they can be hyperechoic, hypoechoic with posterior acoustic enhancement, anechoic, or of mixed echogenicity with internal cystic spaces. With a typical trauma history, follow-up US in 3 to 6 months is suggested to confirm resolution.[3]

 

Galactoceles are milk retention cysts resulting from lactiferous duct obstruction. They are predominantly seen in pregnant or lactating women and are rare in infants and adolescents. US shows a complex cystic mass with variable internal echogenicity depending on its fat and water content. Fat-fluid levels within the lesion are considered diagnostic (Figure 6).[3] [5]

 

Figure 6. A 23-year-old lactating female presented with a palpable lump in the left breast at 10 o’clock position. (a) Targeted ultrasound (US) in transverse plane shows a hypoechoic and anechoic lesion with a fat-fluid level (arrow) and posterior acoustic enhancement. (b) Doppler US study shows no internal vascularity. Fine needle aspiration confirmed the diagnosis of galactocele.

 

Cysts are uncommon in paediatric patients and are usually solitary.[1] A cyst appears as an avascular anechoic lesion with thin wall and posterior acoustic enhancement on US, indicating benignity. Infected cysts may contain internal echoes, fluid-fluid levels, thickened walls, and peripheral hypervascularity.[7]

 

Mastitis refers to infection or inflammation of breast tissue. In the first 2 months of life, mastitis neonatorum can occur due to mammary ductal obstruction or skin breaks permitting bacteria seeding.[7] Puerperal mastitis can affect pregnant or breast-feeding women. The most common pathogen is Staphylococcus aureus.[7] [8] On US, mastitis may appear as focal or diffuse ill-defined heterogeneous hypoechoic and hyperechoic areas, with overlying skin thickening. Colour Doppler may show hyperaemia with central flow (Figure 7).[1] [3] [4]

 

Granulomatous mastitis may be idiopathic or due to systemic conditions, including autoimmune diseases, diabetes, or tuberculosis. These should be excluded before diagnosing idiopathic granulomatous mastitis. Over 50% of cases showed an irregular hypoechoic parallel mass with tubular extensions on US (Figure 8).[9]

 

Figure 7. A 24-year-old female presented with fever and mastalgia for 5 days during breastfeeding. Physical examination found erythema in the lower outer quadrant of the left breast. Targeted ultrasound shows an ill-defined area of altered echotexture and loss of the normal parenchymal pattern (a). The subcutaneous fat appeared hyperechoic, while the glandular parenchyma was hypoechoic with increased central blood flow on colour Doppler (b). The overlying skin was thickened and hyperechoic. The features were suggestive of puerperal mastitis.

 

Figure 8. A 27-year-old female presented with a 1-week history of increasing left breast swelling and erythema, which persisted despite antibiotics. (a) Ultrasound showed an irregular hypoechoic mass with tubular extensions (arrows) in the subareolar region of the left breast. There was associated oedema in the adjacent fibroglandular tissue and mild overlying skin thickening. (b) The mass showed peripheral vascularity on colour Doppler, mimicking a breast abscess. Incision and drainage confirmed the diagnosis of granulomatous mastitis. Acid-fast bacilli smear and culture were negative.

 

Breast abscesses are often seen as anechoic or hypoechoic lesions with debris and posterior acoustic enhancement on US. In contrast to mastitis, abscesses show only peripheral flow.[7] [8]

 

Infantile mammary duct ectasia refers to retroareolar ductal dilatation in infants and young children. The exact cause is unknown.[3] Patients may be asymptomatic or present with bloody nipple discharge.[3] US demonstrates a cluster of tubular anechoic structures with or without internal debris.[3] Associated simple or multiloculated cystic lesions may also be seen.[3] The condition typically resolves after breastfeeding ceases.[3]

 

Intramammary lymph nodes, found in the breast and axillary tail, may become reactive due to inflammation, infection, or recent vaccination. Suspicious features include eccentric cortical thickening of more than 3 mm, extracapsular extension, loss of fatty hilum, or non-hilar blood flow; all require tissue sampling.[3]

 

Infantile haemangioma (IH) is the most common benign neoplasm in infants and can occur in the breast.[8] [10] It is typically absent at birth, rapidly proliferates in the first few weeks to months of life and usually reaches its maximal size by 3 months of age, then spontaneously involutes from 12 months of age, with complete regression by 4 years old in most cases.[3] US or MRI are mainly for treatment planning. During proliferation, IH appears as a well-defined solid mass with a lobulated border of mixed echogenicity on US, with marked diffuse increased vascularity (Figure 9), followed by the plateau phase where it stops enlarging. Finally, IH decreases in size and vascularity during the involution phase. Echogenic areas may be identified, suggestive of fibrofatty tissue. Other vascular tumours such as congenital haemangioma and tufted angioma are uncommon.[10]

 

Figure 9. A 4-month-old female infant was noted to have a rapidly enlarging right breast mass since 2 weeks of age. Targeted ultrasound [US] (a) shows a mixed hypoechoic and hyperechoic mass in the right breast with multiple dilated vessels on colour Doppler US (b), compatible with the clinical diagnosis of infantile haemangioma.

 

Lymphangiomas are benign developmental lymphatic tumours, most frequently in the neck or axilla, but may also affect the breast. Usually presenting before 2 years of age, they appear as avascular compressible multiseptated cystic masses on US (Figure 10) and T2-hyperintense lesions without an enhancing solid component on MRI3 (Figure 11).

 

Figure 10. A 1-month-old male infant found to have a soft fluctuant right anterior chest wall mass since birth. (a) Targeted ultrasound (US) revealed a multilocular anechoic cystic mass with lobulated margins and posterior acoustic enhancement at the subcutaneous layer with no solid component (arrows). (b) Colour Doppler US shows no internal vascularity within the mass. Features were consistent with lymphangioma.

 

Figure 11. A 14-year-old boy presented with right breast swelling for 6 months. (a) T2-weighted magnetic resonance imaging (MRI) with fat saturation. (b) Post-contrast T1-weighted MRI with fat saturation. MRI shows a multiloculated T2-hyperintense mass with thin internal enhancing septations in the subcutaneous layer of the right upper anterior chest wall (arrows). No enhancing solid component was seen. Fine needle aspiration confirmed the diagnosis of lymphangioma.

 

Fibroadenoma is the most common benign fibroepithelial tumour in females under 30 years of age, arising from stromal and epithelial tissues and accounting for 54% to 94% of breast masses in children and adolescents.[5] Masses reaching 5 cm are termed giant fibroadenomas.[3] [5] Juvenile fibroadenoma is an uncommon variant with hypercellular stromal proliferation that can grow rapidly and cause skin distortion.[1] [4] [5] On US, fibroadenoma typically appears as a well-circumscribed hypoechoic parallel mass with variable posterior enhancement and sometimes a pseudocapsule. Fibroadenomas in up to one-third of young breasts are vascular7 (Figure 12a).

 

Figure 12. A 17-year-old female presented with bilateral self-palpated breast masses. Initial ultrasound (US) showed multiple hypoechoic lesions in both breasts (not shown). A follow-up US was performed 1 year later. (a) In the left breast at 6 o’clock position 2 cm from the nipple, an oval parallel circumscribed and hypoechoic lesion with mild vascularity on colour Doppler US was stable in size. (b) In the left breast at 6 o’clock position in the subareolar region, an oval parallel circumscribed and hypoechoic lesion showed interval increase in size, with mild vascularity on colour Doppler US. (c) In the right breast at 12 o’clock position, an oval parallel microlobulated and hypoechoic lesion also showed interval enlargement, without increased Doppler flow. Surgical excision was performed. Pathology showed fibroadenoma and a benign phyllodes tumour in the left breast, and pseudoangiomatous stromal hyperplasia (PASH) in the right breast, corresponding with findings on US. This highlights the occasional similar appearances of fibroadenoma, phyllodes tumour, and PASH.

 

Phyllodes tumour is another fibroepithelial tumour of cellular stroma with branching leaf-like epithelium-lined cystic spaces, typically presenting as a rapid growing mass.[3] It may look sonographically identical to fibroadenoma, appearing as an oval homogeneous hypoechoic circumscribed parallel solid mass[3] (Figure 12b). Phyllodes tumours are classified as benign, borderline or malignant subtypes; however, all types may recur and metastasize, especially to the lungs.[3] In all, 85% of phyllodes tumour in children and adolescents are benign.[5] As imaging findings and fine needle aspiration do not distinguish benign from malignant phyllodes tumour, core needle biopsy is essential.[4] [5] Wide local excision with negative margins is recommended to minimise local recurrence.[3]

 

Pseudoangiomatous stromal hyperplasia is a rare benign localised stromal overgrowth, possibly mediated by hormones.[3] [5] It is usually an incidental finding on histological analysis but can also present as a lump with variable sonographic appearance, sometimes seen as an oval circumscribed hypoechoic or heterogeneous mass (Figure 12c).[3] [4] [8] Surgery is indicated for symptomatic or enlarging masses, but recurrence may occur.[3]

 

Intraductal papilloma arises from benign epithelial proliferation of central mammary duct, projecting into and possibly obstructing the duct, causing nipple discharge at presentation.[1] It is uncommon in children and adolescents, and rare in boys.[5] [8] Typically solitary, it may appear as a well-defined solid nodule within a dilated duct on US (Figure 13),[3] often with a vascular feeding pedicle seen on colour Doppler.[11]

 

Figure 13. A 25-year-old female presented with left nipple discharge. (a) Transverse plane. (b) Longitudinal plane. Ultrasound shows a dilated central mammary duct (arrows) in the left breast periareolar region at 4 o’clock position associated with intraductal soft tissue nodule. Subsequent biopsy confirmed intraductal papilloma.

 

Juvenile papillomatosis occurs when there is localised proliferation with multiple papillomas in the peripheral ducts. Unlike intraductal papilloma, there is no fibrovascular core.[3] Ill-defined hypoechoic masses are seen on US; the presence of multiple peripheral cystic spaces with a ‘Swiss cheese’ appearance hints at the diagnosis.[4] On MRI, they are T1 hypointense showing avid enhancement, with internal T2-hyperintense cystic spaces (Figure 14).[1] [3] Although juvenile papillomatosis is benign, up to 80.4% of patients have coexisting atypical or neoplastic lesions, and it is a marker of familial breast cancer.[3] [11] This signifies the importance of close follow-up screening given the increased lifetime breast cancer risk.[1] [3] [4] [5]

 

Figure 14. A 22-year-old female with biopsy-proven papillomatosis involving both breasts. (a) On ultrasound, the largest lesion in the left breast lower inner quadrant 2 cm from the nipple is shown to be a lobulated mass with a cystic component (arrow) and an associated dilated duct (arrowheads). Transverse plane (left) and longitudinal plane (right). (b-e) Magnetic resonance imaging shows the same lesion (arrows) to be T1-hypointense with avid contrast enhancement (d) and T2-hyperintense (c). A maximum intensity projection of the post-contrast study with subtraction (e) shows multiple avidly enhancing lesions in both breasts (arrowheads), in keeping with the diagnosis of juvenile papillomatosis.

 

Primary breast cancer is rare in paediatrics and young adults. It accounts for approximately 0.1 case per million in females younger than 20 years old, and even less in males.[1] Approximately half of the patients under 30 years old with breast cancer harbour a germline mutation, such as BRCA1/2, TP53 for Li-Fraumeni syndrome, and PTEN for Cowden syndrome.[12] Hence, the diagnosis of breast cancer in young patients should prompt genetic testing and counselling.[1] [3] Individuals over the age of 25 years from a family with known BRCA1/2 mutation carriers should undergo genetic testing. All females with a lifetime breast cancer risk of over 20% are recommended to begin undergoing annual screening MRIs from the age of 25 years with additional annual mammography from the age of 30 years.[13]

 

In 2020, the International Guideline Harmonization Group recommends breast cancer screening in females with a history of chest radiotherapy with radiation dose of over 10 Gy, or previous upper abdominal radiotherapy, given the increased risk for breast cancer.[14] They include childhood cancer survivors such as those with supradiaphragmatic Hodgkin lymphoma who underwent chest irradiation, and haematopoietic cell transplant recipients who had total body irradiation. The elevated risk begins 8 years after treatment and remains increased beyond 40 years.[14] These cancer survivors who develop breast cancer after radiotherapy are reported to have higher mortalities than women with de novo breast cancer in the general population.[14] The National Comprehensive Cancer Network Clinical Guidelines suggest that annual breast MRI and mammography should begin 10 years after treatment, but not before age 25 years and 30 years, respectively, while the Children’s Oncology Group Guidelines (2018 version 5) recommend annual mammography and breast MRI to commence 8 years after treatment or at 25 years of age, whichever is later.[14]

 

Radiological features considered suspicious in paediatrics are no different from adults. On US, concerning features include spiculated margins, microlobulation, marked hypoechogenicity, and not being parallel to the chest wall (Figure 15). On mammography, an irregular, high-density mass with spiculated or indistinct borders; and microcalcifications with fine pleomorphic, linear, or linear branching morphology; and linear or segmental distribution are worrisome for malignancy (Figure 16). Suspicious MRI findings include an irregular mass with spiculated margins and heterogeneous enhancement; or clumped, heterogeneous, or homogeneous non-mass enhancement with linear or segmental distribution; and plateau or washout enhancement kinetics. However, there is overlap of enhancement kinetics between benign and malignant lesions, and persistent enhancement cannot exclude malignancy[15] (Figure 17).

 

Figure 15. A 26-year-old female presented with a right breast mass. Ultrasound shows two closely related microlobulated hypoechoic lesions at 8 o’clock position (arrows). Core biopsy showed atypical ductal hyperplasia. On surgical excision, the histological diagnosis was low-grade intraductal carcinoma arising in a fibroadenoma. In view of this early-onset breast cancer, genetic testing was performed and found the pathogenic PTEN variant, consistent with Cowden syndrome.

 

Figure 16. A 21-year-old female presented with a highly suspicious right breast mass. Mammography with craniocaudal (a) and mediolateral oblique views (b) show an irregular high-density mass in the upper outer quadrant, associated with fine pleomorphic microcalcifications (arrows). Ipsilateral axillary lymphadenopathy was present. The biopsy and surgical specimens yielded invasive ductal carcinoma with ipsilateral axillary nodal metastasis (arrowheads in [b]).

 

Figure 17. A 28-year-old female with known Li-Fraumeni syndrome and a family history of breast cancer. She had a history of left ovarian teratoma and right primary ovarian neuroectodermal tumour treated with salpingo-oophorectomy at 12 years and 13 years of age, respectively. A germline TP53 gene mutation was detected; therefore, she underwent magnetic resonance imaging (MRI) screening for breast cancer (a). A T1-weighted post-contrast MRI with subtraction shows linear non-mass enhancement in the left breast 11 o’clock position (arrow) which demonstrated a type I enhancement curve, new since her prior MRI 2 years ago (b). There was no mammographic or sonographic correlation. MRI-guided vacuum-assisted biopsy showed atypical glands. Surgical excision was performed and confirmed high-grade ductal carcinoma in situ, indicating that a type I–enhancing kinetic curve does not exclude a malignancy (c).

 

Breast metastases are more common than primary breast malignancies in paediatric patients, most frequently from rhabdomyosarcoma (Figure 18), followed by neuroblastoma, haematological malignancies including lymphoma and leukaemia, and Ewing sarcoma.[1] [3] [4] Breast metastases are usually large and solitary with variable US features, which can be irregular or lobulated, heterogeneous, and hypoechoic with hyperechoic foci.[1] [8] Rhabdomyosarcoma and Ewing sarcoma can also involve the breast directly as a primary chest wall malignancy, where evaluation of disease extent with cross-sectional imaging is often helpful.[1] [3] Lymphoma, most commonly non–Hodgkin lymphoma, can affect the breast and ipsilateral axillary lymph nodes primarily, but is exceedingly rare due to the lack of lymphoid tissue in the breast.[3]

 

Figure 18. A 29-year-old female with biopsy-proven alveolar rhabdomyosarcoma in the nasopharynx (arrow) as shown on a sagittal post-contrast T1-weighted image (a). (b, c) A staging ¹⁸F-fluorodeoxyglucose positron emission tomography–computed tomography shows a hypermetabolic mass at 3 o’clock position in the left breast (arrowheads). Subsequent biopsy and left mastectomy confirmed a rhabdomyosarcoma metastasis in the left breast.

 

According to the ACR Appropriateness Criteria,[2] US is the most appropriate radiological procedure for initial evaluation of palpable breast masses in females under 30 years of age. Lesions with benign US features can be followed up clinically. Sonographic features of benign breast lesions include circumscribed margins, orientation parallel to the skin, and less than three gentle smooth lobulations. Short interval follow-up is recommended for probably benign lesions.[2]

 

Developing breast buds in paediatric patients are vulnerable to injury from biopsy, with potential long-term consequences including permanent disfiguration. Therefore, image-guided biopsy should be carefully considered and discussed. Biopsy should be reserved for probably benign masses smaller than 4 cm showing atypical US features or rapid enlargement, probably benign masses that are larger than 4 cm, or masses that demonstrate malignant features on US.[1] In high-risk patients with known genetic mutations, prior irradiation, or extramammary malignancies presenting with an enlarging breast mass, biopsy should be considered even if the US findings appear benign.[1] [3] Core biopsy is preferred over fine needle aspiration due to higher sensitivity, specificity, and accuracy in histological grading, while tumour receptor status can also be tested.[2] Surgical excision may be indicated for rapidly enlarging or symptomatic breast masses even if they show benign radiological features or biopsy results, as phyllodes tumours cannot be excluded.[1]

 

The majority of breast lesions in females under 30 years of age are benign, but malignancies do occur. Radiologists must be familiar with the diagnostic approach and able to identify lesions suitable for follow-up to minimise unnecessary intervention. Prior to biopsy, the potential long-term consequences on breast development in young patients must be considered. When early-onset breast cancer is suspected or diagnosed, it is important not only to review the patient’s medical history but also to explore possible hereditary predispositions.