Cutaneous metastasis emerging during chemotherapy and progressing during immunotherapy for urothelial carcinoma

INTRODUCTION: Cutaneous metastasis of urothelial carcinoma is uncommon. We experienced a case of cutaneous metastasis that emerged during chemotherapy and progressed rapidly during immunotherapy for bladder tumor with lymph node metastasis. CASE PRESENTATION: A 77‐year‐old female patient received chemotherapy using gemcitabine and cisplatin for bladder urothelial carcinoma with para‐aortic and pelvic lymph node metastases (clinical stage T2N1M1). After eight courses of chemotherapy, skin rash appeared in the lower abdomen with leg edema caused by multiple lymphadenopathy. Skin biopsy revealed cutaneous metastasis of urothelial carcinoma. The cutaneous tumor progressed rapidly and the patient died 5 weeks after the start of second‐line pembrolizumab treatment. CONCLUSION: A patient with cutaneous metastasis of urothelial carcinoma that emerged during chemotherapy had poor prognosis and lack of efficacy of an immune checkpoint inhibitor.