Neuroendocrine tumor of the common bile duct: case report.

Neuroendocrine tumors (NET) are a very heterogeneous group of neoplasms; in recent years we have seen an increase in their incidence (3.65 /100.000/year). They can be associated with hereditary endocrine syndromes (MEN, Von Hippel Lindau); they can occur at any age and the incidence is slightly higher in men than women. The aetiology of the neuroendocrine tumors is unclear; in most cases, inflammation of the bile ducts may be the underlying cause and for this reason, the initial patient's evaluation should be focused on the different aspects concerning the oncological one and the possible sequelae of the biliary obstructions that can evolve in biliary sepsis. All neuroendocrine tumors have malignant potential. The most frequent sites of extrahepatic biliary NETs are the common hepatic duct and the distal common bile duct (19.2%), followed by the middle of the common bile duct (17.9%), the cystic duct (16.7%), and the proximal common bile duct (11.5%). We can divide them into: well-differentiated and poorly differentiated. Considering the clinical features, neuroendocrine tumors can be divided into functional and non-functional. As regards the staging, we distinguish localized, regional and metastatic tumors. Tumors derived from the bile duct are difficult to diagnose preoperatively, mainly because of its low incidence and difficult diagnostic process. However since cholangiocarcinomas account for about 80% of all primary biliary tumors, it is important to think about other options despite their low frequency when a patient presents with abnormal characteristics. The most sensitive immunohistochemical markers are expressing neuron-specific enolase, synaptophisin and chromogranin A. Liver function tests, alkaline phosphatase and bilirubin are often high. Sometimes an anemia can appear in the presence of a chronic disease or in patients with more advanced disease. It is known that the measurement of chromogranin A is useful for the preoperative diagnosis of neuroendocrine tumors. Chromogranin A is elevated in 90% of neuroendocrine tumors of the intestine, and the levels correlate with tumor burden and the possibility of recurrence and, therefore, chromogranin A can be an effective biological marker for preoperative diagnosis of neuroendocrine tumors. Bile endocrine tumors remain silent until metastasizing or growing into neighboring organs, because of its uncommon diagnosis in early stages due to its low incidence, absence of serum markers and lack of symptoms related to the hormonal pattern. Preoperative diagnosis of common bile duct carcinoma is extremely difficult, because it is foretold by non-specific symptoms that include pain or discomfort in the right upper quadrant level and weight loss. A 51- year-old woman presented a jaundice and severe bile duct dilatation. The enhanced CT scan showed a mass, approximately 15 mm in diameter, in the distal common biliary duct. The MRI and ERCP confirmed the mass. Cromogranin A value was negative. The diagnosis of well differentiated endocrine tumor of the biliary tract was done after its surgical resection was performed. The postoperative period was uneventful. Extrahepatic biliary NETs are rare, and extrahepatic bile ducts reportedly account for only 0.32% of primary NET sites. The prognosis for NET of the bile duct appears to be poor.