Metastatic perivascular epithelioid cell tumor responding to mammalian target of rapamycin inhibition

Perivascular epithelioid cell tumors (PEComa) are a family of rare mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. Female genital tract and retroperitoneum are common sites of origin of PEComa-not otherwise specified. Diagnosis depends upon characteristic morphology and immunohistochemistry findings. Prognosis of unresectable or metastatic disease is poor. Responses to mammalian target of rapamycin (mTOR) inhibition are encouraging but mostly short-lived. We report a case of metastatic PEComa who responded to mTOR inhibition, albeit for a short duration. We also review the existing literature on mTOR inhibitors in PEComa.