One hundred renal pelvic washings were reviewed blindly for 12 cytologic features. Of 52 washings with tissue confirmation, the cytologic diagnosis suggestive of or positive for transitional cell carcinoma (TCC) was made in 36 cases; 11 were negative, and 5 were unsatisfactory. Of 36 positive washings, histology confirmed the TCC diagnosis in 35 but revealed only reactive changes in 1. Of 11 negative washings, 9 were histologically negative for TCC, and 2 were positive for high-grade TCC. Among 48 washings without tissue confirmation, 33 were negative for TCC or showed reactive changes, 12 were negative for high-grade dysplasia or malignancy, but low-grade TCC could not be ruled out, 1 was suggestive of malignancy, and 2 were unsatisfactory. Clinical follow-up revealed no TCC. Predictive cytologic features of high-grade TCC were high nuclear/cytoplasmic ratio, isolated cells, anisonucleosis, nuclear hyperchromasia, and coarse chromatin; for low-grade they were presence of more than 5 papillary groups, cellular overlapping, anisonucleosis, and hyperchromasia. The sensitivity and specificity for the cytologic diagnosis were 89% and 97% for high-grade TCC and 100% and 78% for low-grade TCC, respectively.
Renal pelvic washings can be used to accurately diagnose TCC of the renal pelvis. The positive predictive value for high-grade TCC is 93%, but for low-grade tumors it is 43%.