Clinicopathologic analysis of renal epithelioid angiomyolipoma: Consecutively excised 23 cases

Renal epithelioid angiomyolipoma (eAML) is considered a malignant variant of angiomyolipoma (AML). From 2001 to 2016, a total of 570 patients were diagnosed with renal AML in Linko Chang GungMemorial Hospital, Taiwan, including 23 cases of renal eAML. All 23 eAML cases were made up of at least 10% of epithelioid cells histologically. Three of these cases were found with multiple tumors. Two cases developed distant metastasis: one had mediastinal lymph nodes and bilateral lung metastasis; the other one had tumor recurrence over liver and retroperitoneum 1 year after radical nephrectomy. They were then divided into invasive (n = 5) and noninvasive (n = 18) groups according to their clinical behavior. The invasive group showed more severe nuclear atypia and higher rates in tumor necrosis. There was statistically no significance in relation to a patient's age, tumor size, and mitotic count between two groups. After conducting a series of studies, we suggest treating eAML with the guideline of renal cell carcinoma.