Extrahepatic bile duct malignancy is mostly an adenocarcinoma cell type. The squamous cell carcinoma is scarcely reported in the literature. The authors are presenting an interesting case of this rare tumor. A 36-year-old man with obstructive jaundice and epigastric pain was referred to the authors hospital. Blood tests showed direct hyperbilirubinemia and elevated ALP. Imaging studies demonstrated dilated bilateral intrahepatic bile ducts with disproportional fusiform dilatation of extrahepatic bile duct compatible with choledochal cyst type 1. There was also the abrupt narrowing of distal CBD associated with enhancement of irregular periductal soft tissue that suggested a malignant feature. After biliary drainage, the patient underwent pancreaticoduodenectomy with bile duct excision to remove the choledochal cyst and tumor-involved periampullary area, then followed with reconstruction. The pathologic specimen consisted of large polygonal cells with vesicular to fine chromatin nucleus, irregular nuclear membrane, and abundant eosinophilic cytoplasm. There were also extracellular keratin materials and presence of intercellular bridges between tumor cells. This morphology was compatible with squamous cell carcinoma. Therefore, the primary squamous cell carcinoma of distal CBD was diagnosed. Concurrent chemoradiation was administered for adjuvant therapy after post-operative recovery. The patient had been doing well for five months after surgery.

Keywords: Bile duct cancer, Cholangiocarcinoma, Squamous cell carcinoma, Adenocarcinoma, Choledochal cyst