A case of Avelumab response to multiple bone and lymph node metastases of plasmacytoid variant bladder cancer.

A 74-year-old man was diagnosed with bladder cancer and referred to our department. For definitive diagnosis, transurethral resection of the bladder tumor(TURBT) was performed. The pathological result showed plasmacytoid variant of urothelial carcinoma. Subsequently, robot-assisted radical cystectomy, lymph node dissection and ileal conduit was performed, but multiple bone metastases and periaortic lymph node metastases newly appeared 30 days later. Gemcitabine and cisplatin (GC) was started, and after 4 courses, the patient became Partial Response (PR), and was switched to Avelumab as maintenance therapy. After about 1 year of maintenance therapy, the patient is still in PR.