Plasmacytoid Bladder Cancer: Variant Histology With Aggressive Behavior and a New Mode of Invasion Along Fascial Planes

Abstract

To examine differences in disease progression and nature of tumor invasion that may lead to more accurate expectations of tumor behavior and improved management options for plasmacytoid variant (PCV) histology urothelial bladder cancer patients. Using the Indiana University Bladder Cancer Database, we conducted a retrospective analysis of patients undergoing radical cystectomy from 2008 to June 2013 to identify patients with PCV, micropapillary variant (MPV), or nonvariant (NV) histology and either positive ureteral margins (+UM), paravesical surgical margins (+PSM), or lymph node (+LN) involvement. Pearson's chi-squared test and analysis of variance were used for descriptive analysis. Of 510 patients who met inclusion criteria, 30 had +UM on final pathology. The incidence of +UM in NV patients was 17 of 457 (3.7%), in MPV 5 of 28 (17.9%), and in PCV 8 of 25 (32.0%) (P <.001). Carcinoma in situ on the luminal margin was noted for all cases, except in 5 of the 8 PCV patients with +UM, in whom retrograde longitudinal invasion along the subserosal and adventitia was noted. +PSM and +LN were significantly higher for both PCV (28.0%, 72.0%) and MPV (10.7%, 64.3%) than NV (2.6%, 18.6%, P <.001, each). PCV exhibits a unique pattern of spread along the ureter. This proposes a new mode of invasion along the fascial sheath. The incidence of +PSM and +LN liken PCV to the known aggressive MPV, and in conjunction with the increased incidence of +UM, may lead to a paradigm shift, with surgeons and pathologists being more vigilant with surgical margins.