Optimizing UroVysion Fluorescence In-Situ Hybridization Reflex Testing in Atypical Urothelial Cell Diagnosis: A...

Area of Science:

• Uropathology
• Cytopathology
• Molecular Diagnostics

Background:

• Urinary cytology is crucial for detecting urothelial carcinoma.
• The Paris System for Reporting Urinary Cytology (TPS) standardizes reports but struggles with Atypical Urothelial Cells (AUCs).
• Variability in AUC diagnosis necessitates improved objective criteria.

Purpose of the Study:

• To investigate the correlation between cytomorphologic features of AUCs and UroVysion fluorescence in-situ hybridization (U-FISH) results.
• To identify specific cytologic parameters predictive of malignancy in urinary cytology.
• To assess the potential of these parameters in classifying cases without reflex U-FISH testing.

Main Methods:

• Retrospective analysis of 121 urinary cytology cases with "atypical" diagnoses.
• Evaluation of 19 cytomorphologic parameters and their association with U-FISH results.
• Correlation with histologic diagnosis, clinical findings, and patient history.

Main Results:

• 31.4% of cases were U-FISH positive, with U-FISH showing 93.5% sensitivity and 91.1% specificity.
• High atypical cellularity, nuclear/cytoplasmic ratio ≥0.7, nuclear enlargement, multinucleation, and mitosis were significantly associated with U-FISH positivity.
• No association was found between TPS AUC criteria and U-FISH positivity; however, parameter combinations showed high positive predictive values (PPVs).

Conclusions:

• Combinations of five specific cytologic parameters, or any four including mitosis, achieved 100% PPV for malignancy.
• Certain parameter combinations indicated moderate PPVs, suggesting a role for reflex U-FISH testing.
• These cytomorphologic features offer potential for improved AUC classification and management decisions.