LOW GRADE UROTHELIAL CARCINOMA

CYTOLOGICAL FEATURES DISCRIMINATING FROM ATYPICAL UROTHELIAL CELLS

Abstract

Objectives: Urine cytology is an easy to perform non-invasive screening test for
patients who are suspected of having urinary tract malignancy. Urothelial carcinoma constitutes
approximately 90% of all primary tumors of urinary bladder.1 High-grade urothelial carcinomas
are represented by well characterized cytological features. Whereas cytological features for
low-grade urothelial carcinomas show considerable overlap with features secondary to chronic
inflammation, calculi, indwelling catheters or effects of intra-vesical chemotherapy.2 The
purpose of this study is to find an appropriate set of cytological features of shed urothelial cells
that will be useful to differentiate low-grade urothelial carcinoma cells from atypical urothelial
cells secondary to non-neoplastic conditions. Study Design: Retrospective study. Setting:
Charsada Teaching Hospital affiliated with Jinnah Medical College Peshawar. Period: 2010
to 2015. Methods: All cases of urine and bladder washing cytology were retrieved for three
diagnostic categories namely: low-grade urothelial carcinoma (LGUC), high-grade urothelial
carcinoma (HGUC), and “atypical urothelial cells”; for which histological diagnoses were also
available. These cases were reviewed for cell clusters with smooth or irregular community
borders, cytoplasm texture, nucleomegaly, high nucleus to cytoplasm ratios (N/C ratio),
presence of nucleoli, nuclear membrane irregularity, and chromatin texture. Results: Cell
clusters with smooth borders were common in reactive changes, whereas irregular community
borders were seen in low-grade urothelial carcinomas and dyscohesive pattern was a feature
of HGUC. The increase in N/C ratio ›2:1 was always associated with malignancy. The nuclear
membrane irregularity was also a strong indicator of malignancy. Cytoplasmic homogeneity
and nuclear hyperchromasia were more prominent and consistently seen in high-grade
urothelial carcinomas. Conclusions: The study showed that nuclear membrane irregularity,
nucleomegaly and high N/C ratio of › 2:1 were the most consistent features found in LGUC.
These features can be used with high certainty to differentiate LGUC (malignant) from atypical
urothelial cells (non-neoplastic).