The value of the "suspicious for urothelial carcinoma" cytology category: a correlative study of 4 years including 337 patients.

Background: The terminology used in reporting urine cytology lacks uniformity and the significance of the "atypical" and "suspicious" categories is still not well established. This results in variable clinical follow-up and management of those cases. The authors sought to investigate the prognostic value of a diagnosis of "suspicious for high-grade urothelial carcinoma" (HGUCA).

Methods: All cases with a "suspicious" or "positive" cytological diagnosis spanning 4 years were included and correlated with the subsequent biopsies obtained within 6 months of urine collection.

Results: A total of 447 correlative events (57% positive and 43% suspicious) corresponding to 773 cytology specimens and 337 patients were included. The morphology of the "suspicious" cells was similar to what has recently been reported in the literature as "atypical urothelial cells, cannot exclude HGUCA." A "suspicious" diagnosis was more often rendered than a "positive" one in voided specimens (80% vs 65%, respectively). The mean interval between cytology and biopsy was 31 days. On follow-up, 92% of "suspicious" diagnoses (176 of 191 diagnoses) and 90% of "positive" diagnoses (230 of 256 diagnoses) were found to have a biopsy with a diagnosis of carcinoma (low grade or high grade). A diagnosis of HGUCA followed a "suspicious" and a "positive" diagnosis in 79% and 86% of cases, respectively.

Conclusions: A "suspicious" diagnosis as defined in the current study warrants close investigations and repeat biopsy to rule out HGUCA. In addition, the findings of the current study raise the question of the need for quantitative criteria for diagnosing HGUCA on cytology.