LAUSR

Synovial Sarcoma is a soft tissue sarcoma with a propensity to imitate a benign neoplasm. It is most common in males 15-40 years old, typically presents as a slow growing painful mass, and often arises insidiously without alarm to the patient. Three patients with synovial sarcomas who had each undergone an index procedure to treat a small presumedly benign mass that was later identified as synovial sarcoma were reviewed. All three patients required re-excision of the tumor and tumor bed and are currently undergoing routine surveillance. All patients exhibited the classic translocation t(X;18) (p11.2; q11.2) and all were of the monophasic type. All lesions were less than 35 mm in greatest longitudinal dimension on MRI. None have experienced recurrences of synovial sarcoma to date. Healthcare providers should be aware of the synovial sarcoma's propensity to masquerade as a benign disease and the characteristic clinical and radiological findings. We advocate for a low threshold to obtain advanced imaging and consideration of a tissue diagnosis prior to excision. A referral to an orthopedic oncologist should be considered and biopsy should only be performed where the definitive treatment will take place if malignancy is identified.