A case of adenosquamous carcinoma of the extrahepatic bile duct associated with bipolar differentiation in the superficial spreading lesion

Abstract

A 73-year-old man was admitted to our hospital for epigastric pain and jaundice. He had undergone en-doscopic mucosal resection for an adenoma of the papilla of Vater at 66 years old. He had suffered from malignant lymphoma at 68 years old, but had complete remission after chemotherapy. On admission, en-doscopic retrograde cholangiography revealed common bile duct stones and stricture of the middle bile duct. Endoscopic lithotripsy, nasobiliary drainage and biopsy were performed. Because histopathological examination of the biopsy specimen revealed adenocarcinoma, pancreaticoduodenectomy was performed. Macroscopically, the bile duct tumor showed papillary invasive type with granular superficial spreading. Histopathological examination of the resected specimen disclosed squamous cell carcinoma invading the subserosal layer in the papillary invasive lesion and adenosquamous cell carcinoma invading the mucosa and fibromuscular layer in the superficial spreading lesion of the upper and lower bile duct. The adenosquamous cell carcinoma showed bipolar differentiation to adenocarcinoma and squamous cell carcinoma. In addition, a small flat invasive type carcinoma of the gallbladder was found. To the best of our knowledge, there has been no report of adenosquamous cell carcinoma of the extra-hepatic bile duct showing bipolar differentiation in the mucosal layer in the 42 Japanese reported cases. So our case is very rare and valuable for investigating the histogenesis of adenosquamous cell carcinoma of the extrahepatic bile duct. © 2011 The Japanese Society of Gastroenterological Surgery.