Cytology of lleal conduit urine in bladder cancer patients: diagnostic utility and pitfalls.

Objective: To study the cytomorphology of urine obtained from the ileal conduit and to determine its utility and identify the pitfalls.
Study Design: Urine specimens from 469 cases of suspected or proven bladder cancer received over a period of 5 years were analyzed in the cytology laboratory. In 35 cases, total bladder resection was followed by ileal conduit reconstruction. The follow-up cytologic analysis of these 35 ileal conduit cases formed the basis of this study.
Results: There was absence of urothelial cells in all but 2 cases. The smear predominantly showed small, scattered intestinal mucosal cells with pyknotic nuclei, extensive karyorrhexis and numerous bacteria. In 2 cases, cytology proved superior to endoscopy and radiology in detecting recurrent disease. We had 2 false negative cases, and the negativity was attributed to sampling errors. There was 1 false positive case in which 3-dimensional clusters of intestinal columnar cells were erroneously diagnosed as adenocarcinoma.
Conclusion: Urine obtained from ileal conduit specimens shows a smear picture that is different from that of specimens from the bladder. Thus, it is imperative to understand the difference between the cytomorphology of bladder urine and ileal conduit urine, to minimize the pitfalls and increase diagnostic utility.