Organ-sparing surgical treatment of muscle-invasive bladder cancer is considered a treatment of choice in carefully selected patients, as it can provide satisfactory survival rates and high quality of life due to preservation of the bladder. However, there is a group of patients who, while meeting the criteria for bladder resection, have an extremely poor prognosis in terms of overall (OS), relapse-free (RFS) and progression-free survival (PFS) due to a certain histological variants of bladder cancer, which necessitates immediate radical cystectomy.

Aim: to investigate the impact of the plasmacytoid variant of urothelial carcinoma of the bladder on both OS, RFS, and PFS rates, and on the tactics of radical treatment of patients with organ-confined bladder cancer who were candidates for organ-sparing treatment at initial presentation.

Materials and methods. The medical records of 215 patients with bladder cancer who underwent surgery between 2020–2025 at the Center for Urology and Urological Oncology of the Feofaniya Clinical Hospital of the State Administration of Affairs were retrospectively analyzed. Among them, we selected patients who harbored elements of plasmacytoid differentiation of urothelial carcinoma in primary transurethral resection of a bladder (TURB) specimen, which has been confirmed by immunohistochemical staining. As a control for assessing survival rates using Kaplan–Meier analysis, an identical number of patients with pure urothelial carcinoma of identical stages, age, gender, and primary treatment tactics who had local recurrence after TURB was selected.

Results. The prevalence of plasmacytoid urothelial carcinoma (PVUC) among our patients with bladder cancer was 1.86 %, or 4 patients. The mean age of the patients was 53.5 ± 10.3 years, and 50 % were men. All survival rates after organ-preserving treatment in the scope of TURB were significantly worse for patients with plasmacytoid urothelial carcinoma compared with pure urothelial carcinoma. The median OS, RFS, and PFS for PVUC were 6 months (p = 0.0177), 1.5 months (p = 0.0067), and 4.5 months (p = 0.0207), respectively. For pure urothelial carcinoma, the median RFS was 17 months, and the median PFS and OS were not reached. In patients with PVUC who underwent emergency radical cystectomy for local recurrence, the median OS, RFS, and PFS were not reached at 12 months of follow-up.

Conclusions. Plasmacytoid variant of urothelial carcinoma is a factor of extremely unfavorable prognosis of overall, relapse-free and progression-free survival of patients after organ-sparing treatment of bladder cancer, compared with pure urothelial carcinoma. Detection of plasmacytoid variant in a biopsy of bladder cancer requires the fastest possible radical cystectomy in order to ensure the best overall survival rates.