Uterine perivascular epithelioid cell neoplasms (PEComas): report of two cases and literature review.

Perivascular epithelioid cell tumors (PEComas) are rare tumors characterized by co-expression of melanocytic and smooth muscle markers. PEComas have been reported in a wide variety of anatomic sites. In the female genital tract, PEComas most frequently affect the uterus. PEComas which occur in non-classic anatomic distributions are known as perivascular epithelioid cell tumor-not otherwise specified (PEComa-NOS). PEComas have an unpredictable biologic behavior, with some tumors being unresectable or metastatic at the time of diagnosis. The risk of aggressive behavior of these tumors has been linked to a number of factors evaluable on histopathological review following initial surgical resection. The authors report two cases of PEComa-NOS of the uterus: one with disease confined to uterus and the other case with lung and liver metastasis.