[Signet ring cell carcinoma of the bile duct: a case report].

A 72-year-old man was admitted with obstructive jaundice. Computed tomography revealed a 4cm tumor with multiple cystic components obstructing the common bile duct. Endoscopic ultrasonography, endoscopic retrograde cholangiopancreatography and intraductal ultrasonography demonstrated the tumor, which derived from the lower bile duct, grew into the bile duct lumen. Peroral cholangioscopy revealed distended tumor vessels on the surface of the tumor. Signet ring cell carcinoma of the bile duct was diagnosed by biopsy. The patient died 3 months after the first hospital admission despite chemotherapy.