Urine cytopathology: Challenges, pitfalls, and mimics

Abstract

Urine cytopathology is a useful and noninvasive tool in the diagnosis and follow-up of urothelial neoplasia, which remains complementary to emerging molecular tests. These specimens may be challenging and there are numerous mimics and diagnostic pitfalls with which to contend. This review discusses these various entities and includes consideration of ancillary tests that may be useful in the diagnostic procedure.

The application of the Johns Hopkins Hospital Template on urine cytology

“…The cytologic features of LGUC include papillary-like clusters, irregular nuclear membrane, increased nucleus-to-cytoplasm ratio, and homogenous cytoplasm; however, these features are overlapping with reactive changes secondary to calculi, inflammation, and instrumentation that contribute to the difficulty in diagnosing LGUC by urine cytology. 9 The two cases of LGUC diagnosed in our study relied on the cell block preparation in which well-defined papillary clusters with fibrovascular core were easily identified.…”

A Modified Direct-Smear Processing Technique Employing Two-Step Centrifugation/Fixation Is Useful for Detecting High-Grade Urothelial Carcinoma

“…For UC detection, screening with urine cytology has been widely used. It is relatively cheap and currently the only noninvasive diagnostic tool, and has played a significant role in the diagnosis and monitoring of individuals [2,3]. However, significant cell loss may occur during the preparation process, and exfoliated cells may deteriorate rapidly and exhibit degenerative changes within 1 h of collection [4].…”

Is a consistent cytologic diagnosis of low-grade urothelial carcinoma in instrumented urinary tract cytologic specimens possible? A comparison between cytomorphologic features of low-grade urothelial carcinoma and non-neoplastic changes shows extensive overlap, making a reliable diagnosis impossible

“…Most of the features were observed almost equally in the study and the control groups. For example, cytoplasmic collars, that were described as a sign of benign processes, 12 were observed in 22.5% of cases in the study group and in 22.6% of control subjects (P Z 0.98).…”

“…12,14 For example, cellular cannibalism or paired cells that were described as a feature of urothelial carcinoma by Hattori et al 15 were also demonstrated in benign processes. 16 Of note, these cells were reported in both highgrade urothelial carcinoma and LGUC cases.…”

“…7,10,11 Although multiple cytomorphologic parameters of LGUC in urine cytology have been described, most of them overlap with benign reactive conditions reflecting the low diagnostic sensitivity. 5,12 Additionally, there is still no agreement on which cytomorphologic features are the most helpful in predicting LGUC and discriminating it from reactive processes. 5,13 In 2013, Mai et al 2 described "3-dimensional cell groups with disordered nuclei and cellular discohesion" as a cytomorphologic feature diagnostic of LGUC (with sensitivity 70% and specificity 94%).…”