Renal cell carcinoma presenting with diffuse peritoneal metastases: CT findings.

Renal cell carcinoma (RCC) spreads predominantly by direct extension, lymphatic dissemination, or venous invasion. Intraperitoneal metastatic spread of RCC involving mesentery and omentum is very uncommon. We report three unusual cases of RCC in which widespread diffuse intraperitoneal metastases were present at the time of diagnosis. The CT findings in these cases included extensive ascites, widespread omental infiltration, and peritoneal implants, as well as retroperitoneal metastases.