Papillary renal cell carcinoma comprises approximately 10% of all renal cell carcinomas. This subtype has a slower growth pattern, has less extensive involvement, and portends a better prognosis than do nonpapillary renal cell carcinomas. Papillary renal carcinomas tend to be avascular or hypovascular on ultrasound examination. It is important not to mistake this lack of vascularity as a sign of benign tumor. The sonographic appearance of papillary renal cell carcinomas is variable, but most display low-level echoes. This case study demonstrates an incidental finding of a typical presentation of papillary renal cell carcinoma in a patient with no symptoms.
