Tuberous Sclerosis Complex Associated Renal Cell Carcinoma with Leiomyomatous Stroma

This case report is about an unusual subtype of renal cell carcinoma with distinct morphological pattern in a 24-year-old female patient with tuberous sclerosis complex. She presented with pain in the left flank and an Magnetic Resonance Imaging (MRI) upper abdomen showed a solid cystic lesion in the interpolar region of left kidney, measuring 2.8×2.8×2.8 cm. She underwent partial nephrectomy which revealed a solid cystic tumour. Microscopically, the tumour was composed of long branching tubules lined by cells with voluminous clear/ vacuolated cytoplasm. A prominent fibromyomatous stroma was seen focally, separating the tumour into nodular aggregates. Tumour cells were positive for Cytokeratin 7 (CK7) on immunohistochemical study. These features were consistent with renal cell carcinoma with leiomyomatous stroma. Genetic study showed a heterozygous nonsense variation in Tuberous Sclerosis 1 (TSC1), gene, diagnostic of tuberous sclerosis. This report exemplifies the pivotal role pathologists play in the initial identification of certain hereditary cancer syndrome. The distinct morphology and immunohistochemical profile of the tumour is described.