Abstract
INTRODUCTION: The safety and efficacy of pembrolizumab administration in patients with urothelial carcinoma and underlying autoimmune disease (including overlap syndrome) is unknown. CASE PRESENTATION: We present the case of a 67-year-old woman with cT3N2M0 metastatic renal pelvic cancer who had been treated with prednisolone for overlap syndrome involving systemic sclerosis and systemic lupus erythematosus for 20 years. She had a remarkable response to pembrolizumab as a third-line systemic therapy, wherein the tumor reduced in size and all regional lymph node and pulmonary metastases disappeared. She did not develop any immune-related adverse events or autoimmune disease flare-ups during the treatment. CONCLUSION: This case report suggests that pembrolizumab could be beneficial to patients with urothelial carcinoma and underlying well-controlled overlap syndrome.