Composite renal cell carcinoma and angiomyolipoma in a patient with Tuberous sclerosis: A diagnostic dilemma.

Tuberous sclerosis (TS) is an autosomal dominant disorder associated with various renal pathologies, including angiomyolipoma (AML). Renal cell carcinoma (RCC) with concomitant AML is rare. We report a case of composite RCC and AML in a young male with TS. This 25-year-old male presented with an abdominal mass. The abdominal computed tomography scan revealed RCC in the left kidney and AML in right kidney. A left radical nephrectomy was performed. Microscopy showed a tumour composed of closely intermingled RCC and AML components. Immunohistochemistry was performed for confirmation. A diagnosis of composite tumour with clear cell RCC and AML was made. Though the coexistence of RCC with AML is rare, and the composite variant is even rarer, one must be aware of this entity to prevent misdiagnosis as well as upstaging of RCC, and also to avoid missing areas of RCC within a large AML, especially in TS patients.