Multidetector computed tomographic features of oncocytic papillary renal cell carcinoma, a new subtype.

Overview

The following report describes the computed tomographic (CT) features of oncocytic papillary renal cell carcinoma (OPRCC), a new subtype. An experienced genitourinary pathologist identified each tumor as type 1 or 2, oncocytic, or other. Two radiologists independently reviewed CT images and assessed maximal tumor diameter, degree of homogeneity, calcification, enhancement, and growth pattern. The 6 OPRCC lesions varied from 1.8 to 5 cm in diameter with a mean of 3.5 cm. Three of the oncocytic lesions were staged T1a, 2 T1b, and 1 T3a. All lesions displayed exophytic growth and were confined to the kidney. Five of the 6 lesions were smooth, and 1 was lobular. Four were homogenously enhancing, whereas 2 were heterogeneously enhancing. The mean (SD) corticomedullary phase enhancement was 70.6 (21.7) HU, nephrographic phase was 69.9 (13.3) HU, and excretory phase was 58.7 (6) HU. In conclusion, OPRCC is a newly described subtype that has CT features similar to type 1 papillary renal cell carcinoma.