Primary Synovial Sarcoma of the Uterine Cervix: First Case Report

Synovial sarcoma is a translocation associated soft tissue malignancy frequently affecting young adults. The classic translocation is t(X;18)(p11.2;q11.2): SS18-SSX1/2/4 fusion. Synovial sarcoma tends to favor the distal extremities but can also arise in other locations. To date, no case of primary synovial sarcoma of the uterine cervix has been reported. We report a 42-yr-old woman with no prior history who presented to clinic with vaginal spotting for 3 mo and was found to have a large mass in the uterine cervix. The mass was evacuated from the vagina and sent for pathologic diagnosis. Sections showed proliferation of monotonous spindle cells with scant eosinophilic cytoplasm, round to slightly irregular nuclei, variable nucleoli and frequent mitosis in a background of delicate capillary and occasional thick-walled vessels. No malignant epithelium was identified in the entire specimen. On immunohistochemical workup tumor cells were negative for pan cytokeratin, OSCAR, EMA, chromogranin, S100, SMA, desmin, myogenin, WT1, CD117, CD34, and BRG1. CD45 was positive in a few inflammatory cells. Cyclin D1 showed partial weak to moderate nuclear reactivity. CD99 demonstrated strong diffuse membranous reactivity and BCL-2 showed strong cytoplasmic staining in 60% of tumor cells. Florescence in situ hybridization results for EWSR1, BCOR, and CIC gene rearrangements were negative, however, florescence in situ hybridization results for SS18 (SYT) (18q11) gene rearrangement was positive. A diagnosis of monophasic synovial sarcoma was rendered. We review the differential diagnoses of tumors with similar morphology and discuss the diagnostic process. With this case report it is imperative to include synovial sarcoma in differential diagnosis list of sarcomas of uterus and cervix.