Renal arteriovenous malformation with inferior vena caval extension mimicking renal cell carcinoma.

A young lady presented with complaints of right flank pain and a palpable mass. On contrast-enhanced tomography (CECT), a renal mass with extension into the inferior vena cava (IVC) - suggestive of renal cell carcinoma - was diagnosed and she underwent radical nephrectomy with en bloc excision of the IVC thrombus. Histopathology revealed a benign arteriovenous malformation that had extended into the IVC. Arteriovenous malformation should therefore be kept in the list of differentials for a renal mass with IVC extension.