Cytologic processing of ureteral microbiopsies is associated with higher sensitivity for detection of urothelial...

Because of the high rates of false-negative or nondiagnostic ureteral Piranha microbiopsies associated with low cellularity, we assessed the effect of processing these using cytology.

We included 2 groups of 44 consecutive microbiopsies processed from formalin as a standard surgical biopsy and 22 processed by cytology. All samples were from the ureter or renal pelvis or calyx. The cytology samples were collected in alcohol-based media and were prepared with a Cellient cell block only (n = 9) or with a Cellient cell block for the visible particles, together with ThinPrep, to capture the remaining desquamated cells (n = 13).

Malignancy was diagnosed in 5 of 44 conventionally processed microbiopsies (11%) compared with 14 of 22 cytologically processed microbiopsies (64%; P < 0.001), including 1 case with invasion. Nineteen site-matched biopsies from 2 patients had undergone both cytologic and surgical processing, with 8 of 8 cytologically processed biopsies diagnosed as malignant. None of the 11 surgically processed biopsies from the same patients matched for site were diagnosed as malignant. Of the 11, 2 (18%) were suspicious for high-grade urothelial carcinoma and 6 (55%) were considered atypical. Increased sensitivity from cytologic processing appears related to increased cell recovery; large numbers of well-preserved urothelial cells were identified in the ThinPrep (range, 1000-25,000 cells/slide), and a nonsignificant trend was found toward increased urothelium (defined as >200 cells/profile) in the Cellient cell blocks (14 of 22 [64%]) compared with the histologic biopsies (17 of 44 [39%]; P = 0.070).

Cytologic processing of ureteral microbiopsies showed superior sensitivity for detecting high-grade urothelial carcinoma, apparently owing to the increased cellular recovery.