A 74-year-old man was diagnosed with small cell carcinoma arising from the extrahepatic bile duct according to a histological examination of the biopsy specimen obtained during endoscopic retrograde cholangiopancreatography. Additionally, bulky hilar lymphadenopathy was observed, and the patient was treated with the combination of radiation and chemotherapy (cisplatin and irinotecan). Post-therapy, he underwent pancreaticoduodenectomy. The histological examination of the resected specimen revealed no residual cancer cells in the bile duct wall and a small amount of cancer cells in only a single lymph node. Due to this multidisciplinary therapy, the patient showed no signs of recurrence 12 months postoperatively.