[A large para-renal PEComa]

We report the case of a 45-year-old man with a voluminous para-renal mass. The tumor was composed of epithelioid or spindle-shaped eosinophilic and clear cells with some atypia and an elevated mitotic count. The immunohistochemical study was positive for anti-HMB45 antibodies and anti-actin-antibodies and negative for epithelial markers and PS100 antibodies. The diagnosis of epithelioid AML (PEComa) was established. Two years later, recurrence was observed with a voluminous mass in the left upper quadrant of the abdomen, with high cellular density and the same immunohistochemical features. This tumor belongs to the PEComa and is not easy to diagnose clinically and morphologically. The immunohistochemical phenotype is characteristic. AML are usually benign but some epithelioid AMLS outcome can be unfavorable with metastatic dissemination. Criteria of malignancy are not clearly defined in the literature. This case shows that the mitotic count and the tumor size are probably important.