Renal epithelioid angiomyolipoma with malignant behavior

The patient was a 22-year-old woman with a history of tuberous sclerosis who complained of abdominal distention. Computed tomography showed bilateral renal masses with minimal fat tissue that were unlike classical angiomyolipoma (AML), as well as enlargement of the paraaortic lymph nodes, pleural effusion, and ascites, similar to other advanced malignant neoplasms such as renal cell carcinoma and renal sarcoma. We performed a left nephrectomy to relieve the symptoms. A pathological examination revealed that the tumor was composed of polygonal epithelioid cells positive for both αSMA and HMB-45, as well as spindle-shaped cells, while immunoreactivity proved the tumor to be an eAML, a subtype of AML with malignant potential. Although the patient was scheduled for postoperative adjuvant chemotherapy, her condition worsened and she died on postoperative day 24 before receiving chemotherapy. We discuss this case with reference to previous reports.