Plasmacytoid Urothelial Carcinoma of the Urinary Bladder: A Clinicopathologic and Immunohistochemical Analysis of 49 Cases.

Objectives: Plasmacytoid urothelial carcinoma (PUC) of the bladder is a rare histologic variant. We retrospectively analyzed a large series of bladder PUC from a single institution.

Methods: The patients consisted of 44 men and five women with a mean age of 62 years (range, 45-86 years).

Results: PUC was pure in 23 cases and mixed with other histologic types in 26 cases. All PUCs diffusely invaded the bladder wall. Most PUCs lacked immunoreactivity for the retinoblastoma (RB) gene protein (12/32) and E-cadherin (8/30). Of the 44 patients with follow-up information, 25 died of PUC at a mean of 23 months, whereas 19 patients were alive at a mean of 22 months.

Conclusions: Our findings support that bladder PUC is a highly aggressive disease. The lack of E-cadherin expression in PUCs may underlie the distinct discohesive histologic appearance, and abnormal function of the RB gene may be implicated in the development of PUC.