Monophasic synovial sarcoma arising in the vulva: a case report and review of the literature.

Synovial sarcomas most commonly arise in the soft tissue of the extremities. Less commonly, these tumors present in the head and neck, abdominal wall, and other sites. However, synovial sarcoma occurring in the vulvar area is extremely rare. Only 2 previous cases of biphasic synovial sarcoma of the vulva have been reported, but no case of vulvar monophasic synovial sarcoma has been described in the English literature. We report the third case of synovial sarcoma and apparently the first case of monophasic synovial sarcoma arising in soft tissues of the vulva. The patient was a 33-year-old woman who presented for evaluation of a painless vulvar mass. The tumor was located in the deep fibroadipose tissue of the right vulva (6.5 x 4.2 x 3.5 cm). The histology of the lesion was that of a monophasic synovial sarcoma with a hemangiopericytic vascular pattern. A subsequent molecular analysis revealed SYT-SSX2 gene fusion, which confirmed the diagnosis of synovial sarcoma. After an initial wide local excision, the patient developed a recurrence in the right groin and received chemotherapy and additional surgery. The patient is currently disease free, on adjuvant chemotherapy, and being followed up closely.