[A case of primary small cell carcinoma arising from the common bile duct]

Small cell carcinoma is usually seen in the lung, but rarely involves the gastrointestinal tract including biliary tract. A 65 year-old man was admitted because of obstructive jaundice. A smooth-surfaced round intraluminal mass with proximal bile duct dilatation was seen in the proximal common bile duct on endoscopic retrograde cholangiogram. Under the diagnosis of bile duct cancer, pylorus-preserving pancreatoduodenectomy was done. Pathology revealed a 2 cm sized small cell carcinoma in the proximal common bile duct and distal common hepatic duct. On immunohistochemical stain, the tumor cells were positive for neuroendocrine markers CD56 and synaptophysin. After surgery, the patient received 5 cycles of adjuvant chemotherapy with VIP (etoposide, ifosfamide, and cisplatin) regimen. However, the patient died of liver metastasis 12 months after the diagnosis. We report a case of extrapulmonary small cell carcinoma arising from the common bile duct.