Urothelial carcinoma in situ with “early papillary formation” vs “lateral spread/shoulder lesion” of prior high-grade noninvasive papillary urothelial carcinoma a survey of pathologist and urologist interpretations

Objectives: Urothelial carcinoma in situ (CIS) with early papillary formation is terminology sometimes used to suggest incipient high-grade papillary urothelial carcinoma (PUC) but may lead to confusion between true CIS and lateral flat spread of PUC. Methods: It remains unclear how pathologists and urologists interpret this scenario, so a survey was circulated to 68 pathologists (group 1 = 28 academic genitourinary pathologists; group 2 = 17 pathologists with a self-reported genitourinary focus; group 3 = 23 pathologists self-reported as not genitourinary specialists) and 32 urologists. Results: Regarding atypical urothelial lesions that appear mainly flat but contain possible papillae, group 3 was more likely to label this as CIS compared with groups 1 and 2 (35% for group 3 vs 13% for groups 1 and 2), while groups 1 and 2 more often adopted another descriptive diagnosis, such as “CIS with early papillary features” (38% for groups 1 and 2 vs 13% for group 3). Among all 3 groups, group 1 was most likely to diagnose concomitant CIS and PUC in the same specimen but in different tissue fragments (58%). Pagetoid spread was reported to favor CIS predominantly by group 1 (61%). Urologists felt that the term lateral spread/shoulder was unclear (75%) and preferred early PUC (44%) or PUC with early growth (44%). Half (53%) of urologists felt that reporting CIS instead of lateral spread of PUC would change management. Conclusions: Documentation of flat lesions lacks consensus among pathologists and may benefit from standardized terminology. Moreover, the distinction between CIS and early or lateral spread of PUC is not always clear to urologists and can influence disease management.