Radiological features of ankle synovial cell sarcoma

A 23-years-old man was referred to our institution to investigate a painless right ankle mass. The clinical examination found a painful mass, fixed on the superficial and deep plane with vascular turgor. It measured 15x10cm (A). The x-ray of the ankle was done first and revealed opacity centred on the soft external malleolar tissues (Arrow B). Then an MRI was performed. It showed multi lobulated mass with heterogeneous enhancement after injection of gadolinium (C) and a specific triple signal in T2 weighted images (D), made by a hyper signal (liquid), intermediate signal (tumor tissue) and hypo signal (septa). This radiological finding reminds a "bowl of grapes". The extension to the carpal bones was diagnosed as a hyper signal area on T2 (Arrow D). The diagnosis of synovial sarcoma was suggested and then confirmed by pathological analysis after performing a surgical biopsy. The patient has developed a metastatic location in the right thigh. Synovial Sarcoma is a malignant mesenchymal tumor. It presents 10% of all ankle soft tumors, and affects young adults with a sex ratio of 1. The lesion is often slow growing. On MRI, the synovial sarcoma diagnosis strongly suggestive by the classic "triple sign"; and "bowl of grapes sign" in T2 sequences. Its treatment is based on surgical excision adjunctive with chemotherapy or radiotherapy.