Papillary renal cell carcinoma: ultrasonic/pathologic correlation.

Papillary renal cell carcinoma represents a separate clinicopathologic entity distinguished from nonpapillary renal cell carcinoma by angiography, microscopic pathology, and biological behavior. We correlated retrospectively 11 surgically proven papillary renal cell carcinomas with ultrasound patterns and gross pathologic findings. In addition, we reviewed retrospectively 65 surgically proven cases of nonpapillary renal cell carcinoma for sonographic patterns. Seven of 11 (64%) of the papillary tumors were less echogenic than the ipsilateral renal cortex (hypoechoic). Only 23% of the nonpapillary tumors were hypoechoic. These data suggest that renal papillary carcinoma tends to be hypoechoic on ultrasound. In most of the papillary cases, this hypoechoic pattern was due to a large central area of cystic necrosis within the tumor.