Primary extrahepatic biliary neuroendocrine tumor: a case report.

Extrahepatic biliary neuroendocrine tumors (EBNETs) are extremely rare and difficult to diagnose. The vast majority are diagnosed postoperatively on histological evaluation of surgical specimens. Workup and treatment principles are largely based on retrospective series and case reports. Complete surgical resection is the gold standard treatment for these lesions. Here we present a case of a 77-year-old male with a biopsy-proven EBNET incidentally discovered during evaluation for fatty liver disease. Further workup did not show any other suspicious lesions. Resection of the tumor and multiple Roux-en-Y hepaticojejunostomy was performed. Final pathology revealed grade 1, well-differentiated neuroendocrine tumor. This is the third case reported in the literature with a confirmed preoperative EBNET diagnosis based on endoscopic biopsy results. This case highlights the feasibility of preoperative diagnosis of EBNETs and emphasizes the importance of complete surgical resection.