Perivascular epithelioid cell tumor of the uterus: a case report.

A case of perivascular epithelioid cell tumor (PEComa) arising in the subserosa of the uterus of a 32-year old woman is presented. The lesion, removed by local excision, was an unencapsulated rubbery mass 5.0 cm in diameter. The tumor was composed of round to polygonal cells with round nuclei and abundant clear to slightly eosinophilic cytoplasm containing glycogen, and the cells were arranged in short fascicles focally in a perivascular location. There were scattered foci of necrosis and hemorrhage. The tumor cells showed mild atypia and low mitotic activity, and they were strongly immunoreactive for vimentin, h-caldesmon, and HMB45. Ultrastructural examination showed no melanosomes or premelanosomes. The patient had no evidence of disease 8 months postoperatively. Uterine PEComas should be regarded as tumors with an uncertain malignant potential.