Neuroendocrine neoplasms of the extrahepatic bile duct: radiologic and clinical characteristics

To retrospectively identify the radiological and clinical features of neuroendocrine neoplasms of the extrahepatic bile duct. Institutional review board approval was obtained. Between August 2003 and August 2013, 11 patients (range 41-79 years) who had undergone surgery in our institution for neuroendocrine neoplasms of the extrahepatic bile duct were identified. Clinical features (symptoms, laboratory finding, and medical history) were reviewed. A pathologist reviewed the pathology of 11 patients. CT (n = 11), MRI (n = 10), and PET/CT (n = 8) were reviewed by two radiologists in consensus. They were blinded to the clinical features and pathology report. The tumor location was assessed on CT and was classified as occurring in the common hepatic duct, cystic duct, and common bile duct. The tumor shape was assessed in ten patients using MRI and in one patient using CT. The shape was classified as nodular, intraductal-growing, and periductal-infiltrating type. The FDG activity on PET/CT was also evaluated. Correlation of image findings with pathology was made by a radiologist who didn't participate in the image analysis. There were five men and six women and their median age was 65 years. On pathology examination, seven patients had neuroendocrine carcinoma (64%), three had mixed adenoneuroendocrine carcinoma (27%), and one had neuroendocrine tumor (9%). CT showed that the tumors were located in the common bile duct in seven patients (64%), the common hepatic duct in two (18%), and the cystic duct in two patients (18%). Five tumors were classified as nodular (45%), five as intraductal-growing (45%), and one as periductal-infiltrating type (9%). PET/CT showed increased FDG activity, ranging from 2.7-15.9, in eight patients with neuroendocrine carcinoma. The most common location of neuroendocrine neoplasms of the extrahepatic bile duct is the common bile duct. Most of them are nodular or intraductal-growing type.