Key facts
Synonym:extension of tumor into renal vein.
Definition:extension of tumor from a renal neoplasm into the renal vein, and possibly the inferior vena cava (IVC), occasionally right atrium.
Classic imaging appearance:renal vein distended by tumor with visible tumor vessels on color Doppler and tumor enhancement on contrast-enhanced CT or MRI.
Other key facts:(1)renal vein extension occurs with renal cell carcinoma (RCC), Wilms tumor , transitional cell carcinoma , lymphoma; ( 2 ) reported incidence of RCC extension to renal vein 21%-35%, IVC 5%-10%.