Well-differentiated Neuroendocrine Tumors

Comments:
Clinical Features: Well-differentiated neuroendocrine tumors (WDNETs) of gallbladder and bile ducts are exceedingly rare (<1% of all WDNETs of GI tract). They are not associated with Carcinoid syndrome, and often discovered incidentally in cholecystectomies or present with non-specific abdominal symptoms. The mean age at diagnosis is 60 years with a slight female predilection. A small percentage are associated with von Hippel-Lindau syndrome, MEN type I, or Zollinger-Ellison syndrome.

WDNETs of the biliary tract are indolent tumors that can remain clinically silent if small. Their prognosis is similar to the WDNETs elsewhere in the GI tract. Tumors > 2 cm have worse prognosis due to greater risk of extension into the liver and distant metastasis. This image of a WDNET of gallbladder shows solid sheets and nests of a homogenous population of tumor cells separated by delicate fibrous trabeculae.