The patient presented with a swelling on the left neck. A gradually increasing mass lesion of approximately 2cm in diameter had been noted 2 months previously and this mass had rapidly increased in size over the previous 2 days. MR imaging was performed.
The patient presented with a swelling on the left neck. A gradually increasing mass lesion of approximately 2cm in diameter had been noted 2 months previously and this mass had rapidly increased in size over the previous 20 days. On physical examination, there was a firm mass lesion in the left supraclavicular region extending to the left shoulder and neck. The mass was fixed to surrounding tissues. There was no lesion in the right supraclavicular region. Laboratory results were within the normal limits.
Magnetic resonance (MR) imaging was performed. On T1-weighted MR images, there was an isointense mass lesion relative to surrounding muscle tissue in the supraclavicular region extending to the neck. There were also hypointense signals within the lesion (Fig. 1a). The lesion showed prominent contrast enhancement after contrast medium injection and the hypointense component became more prominent (Fig. 1b). The solid component of the lesion displayed isointense signals relative to surrounding muscle tissue on fast spin-echo T2-weighted MR images (Fig. 1c). The necrotic component within the lesion showed increased signals. MR angiography showed a large feeding artery originating from the left vertebral artery (Fig. 1d).
Synovial sarcoma is a rare tumour that constitutes approximately 10% of all soft tissue sarcomas. It is most common in the 2nd and 4th decades of life but may be seen in all age groups (1). The name synovial sarcoma originates from the similarity of the cells with synovial cells which line the surface of joints. Synovial sarcoma is mostly located in tendons and bursae in close proximity to joints. It generally involves the lower extremities, but may be seen in the upper extremities, head and neck region, the wall of the abdomen, and the ankle. The location in the supraclavicular region is relatively rare. In this location it generally originates from the acromioclavicular joint, and it is relatively difficult to differentiate it from lymph node enlargement, which is most commonly seen in that region due to metastatis. The young age of the patient and the absence of findings of primary tumour should alert the physician. Synovial sarcoma of the head and neck region seems to carry a better prognosis than synovial sarcoma of the extremities.
On plain radiographies, soft tissue densities with well-defined contours can be detected in 67% of cases located near joints. Calcifications can be seen in 30% of cases. Bone destruction is detected in 20% of cases because of a pressure effect of the lesion on neighboring bone. The lesion shows increased density compared with muscle on CT scans. CT is better than MR imaging in demonstrating cortical bone involvement and calcifications. Sometimes the lesions show a cystic or haemorrhagic component. Although it is not possible to make a specific diagnosis with MR imaging, some MR imaging features have been described in the literature. Synovial sarcoma can be seen as a heterogeneous multiloculated mass lesion with internal septations. The contour of the lesion is generally well-defined and may have a capsule formation (1-4). The lesions show isointense signals relative to muscle tissue on T1-weighted MR images and hypo- or hyperintense signals on T2-weighted MR images. Recent studies about the dynamic Gd-enhanced imaging in synovial sarcomas showed enhancement of syonovial sarcomas within 7 s after arterial enhancement. This finding was found to be a consistent sign mostly encountered in this tumor (5).
Synovial sarcoma of the left acromioclavicular joint
The patient is a 28-year-old female with a progressively enlarging mass palpable in the left side of the neck. Based on the provided MRI images, there is a soft tissue lesion located in the left neck near the supraclavicular fossa region, characterized by:
Considering the patient’s young age, rapid growth of the mass, and the MRI findings of well-defined margins and enhancement features, the following differential diagnoses are possible:
Based on the clinical history (young patient, palpable neck mass, rapid growth), imaging findings (well-defined margins, septations, multiple signal components, rapid enhancement), and the fact that such tumors are rare in the head and neck region but documented in the literature, the most likely diagnosis is: Synovial Sarcoma.
Since imaging alone cannot completely rule out other soft tissue tumors, a definitive diagnosis requires histopathological and immunohistochemical examination. If necessary, further evaluation through biopsy or surgical resection with pathological assessment is recommended.
For synovial sarcoma and other malignant soft tissue tumors, a multidisciplinary approach is advised:
Treatment via surgery or radiotherapy/chemotherapy can affect physical function, including local soft tissue and joint mobility, as well as overall endurance and muscle strength. Rehabilitation should be individualized, with reference to the following key points:
During rehabilitation, avoid heavy lifting, intense impact, or overstretching of the affected neck area. If persistent pain, swelling, or other discomfort occurs, seek medical evaluation promptly.
Disclaimer: This report is based solely on the provided imaging data and limited clinical information for initial assessment. It does not replace an in-person medical consultation or professional medical advice. Specific treatment and rehabilitation plans should be made under the guidance of a specialist.
Synovial sarcoma of the left acromioclavicular joint
