A case report on malignant perivascular epithelioid cell neoplasm of the thigh, a rare presentation in the skin

Perivascular epithelioid cell neoplasms (PEComa) are a family of mesenchymal tumors characterized by perivascular epithelioid cells with co-expression of melanocytic and muscle markers and can occur in any part of the body. These tumors are almost always positive for HMB-45 and smooth muscle actin (SMA) immunochemistry. Perivascular epithelioid cell neoplasms tend to arise in middle age, and there is a marked female predominance. The tumors most commonly occur in the gynecologic tract, pelvis, and retroperitoneum. They are of varying malignant potential and are occasionally associated with tuberous sclerosis complex, a rare tumor driven by tuberous sclerosis complex gene mutations TSC1/2, causing up-regulation of mTOR. We present a case of malignant perivascular epithelioid cell neoplasm of the thigh, which is an exceedingly rare presentation in the skin.