Primary Synovial Sarcoma of the Orbit: A Case Report and Update on Diagnostic Techniques.

Synovial sarcoma is a malignant mesenchymal tumor that most commonly occurs in the deep soft tissue of the extremities in adolescents and young adults. Primary periocular synovial sarcoma is extremely rare with only 11 previously reported cases. We describe a 23-year-old woman who presented with a 1-year history of painful, progressive right upper eyelid swelling. She was subsequently found to have a superomedial orbital mass on CT scan. Pathologic evaluation revealed a spindle cell neoplasm with SS18 (SYT) rearrangement by fluorescence in situ hybridization studies, consistent with a monophasic synovial sarcoma. This case describes the clinical, radiographic, histopathologic, and molecular cytogenetic features of this rare orbital neoplasm, with an emphasis on the emerging diagnostic techniques and novel therapies.