Aggressive behavior of anaplastic undifferentiated carcinoma arising from the hilar bile duct

BACKGROUND: Undifferentiated carcinoma of the biliary tree is extremely rare, and biliary undifferentiated carcinoma mostly originates from the gallbladder. We herein present a case of anaplastic undifferentiated carcinoma of the hilar bile duct and reviewed the literature. CASE PRESENTATION: The patient was an 81-year-old male with obstructive jaundice. Contrast-enhanced computed tomography (CT) showed a protruded tumor located at the hepatic hilum. Obstructive jaundice was relieved by endoscopic drainage. Endoscopic biopsy revealed carcinoma without glandular differentiation, and the patient was diagnosed with resectable hilar undifferentiated carcinoma. During the 5-week preoperative examination, the tumor increased in size from 23 to 45 mm. Left hemi-hepatectomy and extrahepatic bile duct resection were performed, and there were no postoperative complications. Histological findings demonstrated that the tumor was mainly composed of non-cohesive polygonal neoplasms with pleomorphic nuclei, and was diagnosed as anaplastic undifferentiated carcinoma of the common hepatic duct (T2a N0 M0 Stage II). One month after surgery, the patient was readmitted to our hospital with pyrexia due to cholangitis, and liver nodules suggestive of multiple liver metastases were detected by CT. Three months after surgery, the patient died of multiple liver metastases. CONCLUSIONS: This is the first case report of undifferentiated cholangiocarcinoma with anaplastic features. Anaplastic undifferentiated carcinoma of the hilar bile duct showed preoperative rapid growth and early relapse despite a cancer-negative surgical margin.