[Tumors showing perivascular epithelioid cell differentiation: a clinicopathologic study of 39 cases]

To investigate the clinicopathologic features of tumors showing perivascular epithelioid cell differentiation (PEComas).

The clinicopathologic data of 39 cases pf angiomyolipoma (AML), 17 males and 22 females, with the primary focus in the kidney on 30 cases, in the liver in 4 cases, in the lung, uterus and broad ligament, abdominal wall, retroperitoneum, and nasal cavity in 1 case respectively, were analyzed. Immunohistochemistry (HIC) was used to detect the expression of pan-cytokeratin (CK), S-100 protein, smooth muscle actin (SMA), desmin, vimentin, HMB45, Melan-A, microphthalmia transcription factor (MiTF), CD117, and CD34 in the specimens of the tumors obtained during operation. Twenty patients were followed up.

Pathological examination showed branched capillaries or arterioles, often thick-walled similar to those in the renal cell carcinoma, and the cancerous cells consisting of the mixture of epithelial cells and spindle cells. HIC showed that the expression rates of Melan-A, HMB45, MITF, SMA, desmin, S-100 protein, vimentin, CD117, CK, and CD34 were 95% (37/39), 72% (32/39), 46% (18/39), 82% (32/39), 27% (10/39), 15% (6/39), 82% (32/39), 10% (4/39), 0, and 0 respectively. Clinical follow-up showed 1 patient alive with tumor, and 19 alive free from disease.

PEComas have distinctive morphological and immunohistochemical features.