Successful treatment of metastatic bladder pleomorphic giant cell carcinoma with pembrolizumab

INTRODUCTION: Bladder pleomorphic giant cell carcinoma is a rare and aggressive malignancy with a poor prognosis. There are no reports of immune checkpoint inhibitors for bladder pleomorphic giant cell carcinoma to date. CASE PRESENTATION: A 72‐year‐old man presented with gross hematuria due to multiple bladder cancers. Despite transurethral bladder resection and intravesical injection of Bacillus Calmette–Guérin, bladder cancer recurred. Nineteen months later, he underwent total cystectomy. Pathological examination revealed bladder giant cell carcinoma. Twenty‐eight months later, pembrolizumab was administered due to para‐aortic lymph node metastasis. Forty‐four months later, the lymph node metastasis disappeared, and pembrolizumab administration was terminated. Fifty‐eight months later, the patient has remained in remission at the time of writing. CONCLUSION: Immune checkpoint inhibitors manifest a therapeutic potential in bladder pleomorphic giant cell carcinoma.