Renal epithelioid aggressive angiomyolipoma in a patient with tuberous sclerosis and past contralateral benign renal angiomyolipoma.

Twenty-five percent of all aggressive angiomyolipomas (AMLs) are related to tuberous sclerosis. Our patient was a 42-year-old man with tuberous sclerosis and a medical history of a benign AML in the left kidney. Presently, an epithelioid AML was detected in his right kidney and, despite our conducting extensive surgery, a large pulmonary metastasis with mediastinal lymph node involvement followed 20 months later. Close follow-up of the patient is advised when epithelioid cells are observed in angiomyolipoma. Immunohistochemistry for mismatch repair proteins showed that PMS2, MSH2, and MSH6 were absent in both the tumor and normal kidney. Microsatellite instability may contribute along with a mutation of TSC gene to the oncogenic events leading to AML.