Clinical evaluation of epithelioid angiomyolipoma.

OBJECTIVE Epithelioid angiomyolipomas (AML) of the kidney are malignant tumors with aggressive clinical behavior. METHODS The Authors report on some cases epithelioid AM recently diagnosed at their Institute to highlight the spectrum of clinical presentations. RESULTS In all cases, renal lesions observed at computed tomography were suspicious for renal cell carcinoma (RCC). Histologically, these tumors can resemble RCC. The diagnosis of epithelioid AML was established by positive staining for melanoma and smooth muscle cell markers, and presence of perivascular epithelioid cells. Four patient presented with a renal tumor extending into the inferior vena cava to the level of the hepatic veins. Two patients developed recurrent, metastatic disease following nephrectomy. CONCLUSIONS These tumors are distinguished from RCC by positive immunostaining for melanoma markers and smooth muscle cell markers. They resemble conventional RCC on imaging. Epithelioid AML, may be locally aggressive and metastasized.