Duodenal Neuroendocrine Carcinoma Presenting with Disseminated Liver and Bone Metastases as the Primary Manifestation: Case Report and Literature Review.

Neuroendocrine tumors are composed by a heterogeneous group of tumors with a wide range of morphologic, functional, and behavioral characteristics. These tumors are generally slow growing and behave in an indolent fashion. However, they have the potential to spread, especially for poorly differentiated neuroendocrine carcinomas, and when they do, they can be very aggressive, with high propensity for distant metastases, and difficult to treat with current modalities. As poorly differentiated neuroendocrine carcinomas rarely occur in extrapulmonary sites, to the best of our knowledge, this is the first case report of a poorly differentiated duodenal neuroendocrine carcinoma with diffuse liver and bone metastases as the primary manifestation. Despite receiving a trial of chemotherapeutic regimen, the patient had progressive intrahepatic cholestasis and died of subacute hepatic failure.