Malignant ascites and small renal mass: an unusual presentation of advanced renal cell carcinoma.

Metastatic renal cell carcinoma (RCC) presenting with peritoneal involvement or ascites is rare and has been previously described clinically in the setting of large renal mass or other distant metastases. We report an unusual case of RCC presenting with ascites without large mass or other distant metastases. Advances in cytologic diagnosis of metastatic RCC in serous ascitic fluid is discussed, while a potential mechanism of tumor spread is presented.