A case of mixed adenoneuroendocrine carcinoma of the common bile duct: initially diagnosed as cholangiocarcinoma

[...]due to the limitation involved with obtaining adequate biopsy specimens, ERCP may fail to reach the neuroendocrine component, which is embedded in a deeper portion of the tumor. [...]the pathologic diagnosis of MANEC using a surgically resected specimen with immunohistochemical stainining for neuroendocrine markers (chromogranin, synaptophysin, and CD56) may be useful for the correct diagnosis.3 Even in surgical specimens of biliary tract cancer, NETs and MANECs may be hidden inside the adenocarcinomatous components. Most MANEC cases, including this one, are initially diagnosed as cholangiocarcinoma. [...]the acquisition of a surgical specimen and thorough investigations by the pathologist are crucial to make the correct diagnosis in order to determine the best treatment and estimate the prognosis in extra-hepatic bile duct cancer.