Introduction: Plasmacytoid variant bladder cancer is a rare variant of urothelial carcinoma that accounts for 1% of bladder cancers. Plasmacytoid variant urothelial carcinoma is characterized by an aggressive phenotype and poor clinical outcomes.
Case presentation: A 61-year-old woman presented with gross hematuria. Cystoscopy showed a 16-mm solid tumor. Transurethral resection of the bladder tumor was performed, and the pathological diagnosis was invasive plasmacytoid variant urothelial carcinoma. Although the pathological T stage was pT1, computed tomography showed right obturator lymph node swelling. Since previous reports indicate poor response to chemotherapy for this disease, clinical sequencing was performed. Based on the high tumor mutation burden revealed, pembrolizumab was administered for 4 cycles, and computed tomography showed a partial response. Robot-assisted radical cystectomy was performed, and a pathological complete response including the pelvic lymph node was observed.
Conclusion: Pembrolizumab may be a treatment option for plasmacytoid variant urothelial carcinoma following genomic analysis.
Keywords: bladder cancer; high tumor mutation burden; pembrolizumab; plasmacytoid variant.
© 2022 The Authors. IJU Case Reports published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Urological Association.