Abstract. A case of renal granular cell carcinoma with inferior vena cava and right atrium involvement is presented. Spin-echo and single breath-hold gradient-recalled-echo magnetic resonance pulse sequences demonstrate a patchy flow signal within the cavoatrial thrombus. This pattern, in correlation with the histopathologic findings, represents tumoral neovascularity characteristic of renal carcinoma venous invasion, which was previously reported by angiography, computed tomography, and color Doppler duplex ultrasound.