Clinicopathologic characteristics of extrahepatic biliary neuroendocrine neoplasm: A single center experience of gallbladder, extrahepatic biliary tract and ampulla of Vater

Introduction Neuroendocrine neoplasm of extrahepatic bile ducts are very rare. The aim of this study to elucidate the clinicopathological characteristics, therapeutic approach and prognosis of these patients. Methods The subjects were 16 patients who were diagnosed with neuroendocrine neoplasm or mixed adenoneuroendocrine carcinoma (MANEC) after curative resection. There were 8 ampulla of Vater and 8 non ampulla of Vater (6 gallbladder and 2 distal bile duct). Results The female to male ratio was 1.3/1 with mean age of 57.9 years (ranging from 36 to 74 years). There were 8 cases of incidental diagnosis in health screenings and 2 cases during evaluation for other disease. The most common symptoms were abdominal discomfort (3 pain and 1 dyspepsia) and jaundice (2 cases). According to the 2010 WHO classification, 1 patient had NET G1, 5 NET G2, 6 NET G3 and 5 MANEC. G3 and MANEC were small cell type. Pancreatoduodenectomy was performed in 9 patients (1 combined minor hepatectomy), extended cholecystectomy in 6 cases (1 combined pancreaticoduodenectomy and right hemicolectomy) and radical bile duct resection in 1 case. There were no association between OS and DFS with various clinicopathological factors including TNM stage. Ki-67 (cut-off 20%) was only prognostic factor in OS (5-year survival: 100% vs. 42.3%; p = 0.044) and DFS (5-year survival: 100% vs. 47.6%; p = 0.059). Conclusions In NET of extrahepatic bile duct, the titer of Ki-67 is more important than TNM according to AJCC, and attention of Ki-67 titer may be needed in treatment of recurrence.