The pagetoid variant of urothelial carcinoma in situ.

The frequency, distribution, and clinical significance of pagetoid changes in urothelial carcinoma in situ (CIS) were studied in over 600 tissue slides from 102 patients followed for a mean period of over 4 years. Results indicate that pagetoid changes are unusual, randomly distributed, and never widespread. These changes occur in a histologic setting of CIS and apparently never appear as the initial lesion, even in cases in which CIS is the primary or only neoplasm. Patients manifesting pagetoid CIS had essentially the same progression and survival rates as patients without pagetoid changes. Our data suggest that this histologic pattern represents a peculiar reaction to injury confined to small areas of urothelium in susceptible hosts.