OBJECTIVE: To evaluate and compare the cytopathological expression of the five major histological types of carcinoma in situ (CIS) in urinary bladder washings from patients with flat urothelial lesions. MATERIALS AND METHODS: Seventy-five cases of primary and secondary urothelial CIS with no concomitant tumours, and having tissue and cytological samples, were identified. Biopsies were evaluated based on the consensus classification as: large-cell pleomorphic; large-cell non-pleomorphic; small-cell; clinging; and cancerization of the urothelium. In the cytological classification the 'clinging' category was excluded, as its definition depends on the histological appearance. kappa statistics were used to evaluate the correlation between histopathology and cytology. RESULTS: More than one subtype of CIS could often be identified in both the histological and cytological specimens. Cytology often showed more subtypes than did histopathology. Statistically, there was only a moderate correlation between histopathology and cytology for recognising different patterns. CONCLUSION: Different patterns of CIS can be identified by cytology; it is important for cytologists to be aware of the cytological spectrum of CIS and not to under-diagnose monomorphic, pagetoid (cancerization) and small-cell forms. Studies on treatments for CIS and of the clinical significance of different subtypes of CIS should include both cytopathology and histopathology.
OBJECTIVE: To evaluate and compare the cytopathological expression of the five major histological types of carcinoma in situ (CIS) in urinary bladder washings from patients with flat urothelial lesions. MATERIALS AND METHODS: Seventy-five cases of primary and secondary urothelial CIS with no concomitant tumours, and having tissue and cytological samples, were identified. Biopsies were evaluated based on the consensus classification as: large-cell pleomorphic; large-cell non-pleomorphic; small-cell; clinging; and cancerization of the urothelium. In the cytological classification the 'clinging' category was excluded, as its definition depends on the histological appearance. kappa statistics were used to evaluate the correlation between histopathology and cytology. RESULTS: More than one subtype of CIS could often be identified in both the histological and cytological specimens. Cytology often showed more subtypes than did histopathology. Statistically, there was only a moderate correlation between histopathology and cytology for recognising different patterns. CONCLUSION: Different patterns of CIS can be identified by cytology; it is important for cytologists to be aware of the cytological spectrum of CIS and not to under-diagnose monomorphic, pagetoid (cancerization) and small-cell forms. Studies on treatments for CIS and of the clinical significance of different subtypes of CIS should include both cytopathology and histopathology.