TFE3-rearranged renal cell carcinoma - Morphology and differential diagnosis

TFE3 rearranged Renal cell carcinoma is a newly recognized entity with few reported cases. TFE3 positivity has poor prognosis and requires long term follow up. A 26-year-old woman presented with flank pain since 5 months. CECT revealed an exophytic mass abutting adjacent structures with no infiltration. Radical nephrectomy was done, showing a pale yellow tumour, replacing the kidney. Microscopically the tumour was disposed in papillae composed of clear cells with voluminous cytoplasm. Patient is doing well at 16 months' post-surgery. More studies on the morphology, immunohistochemistry with genetic correlation are needed to determine clinical behaviour, management and prognosis.