Well-differentiated neuroendocrine carcinoma (malignant carcinoid) of the extrahepatic biliary tract: report of two cases and literature review.

The objectives of this study were to evaluate the frequency of carcinoid tumors of the extrahepatic biliary ducts (EHBDs) and the pathologic progression and the role of surgery in the management of this disease. We describe two cases of malignant carcinoids of the EHBDs, which presented as common bile duct tumors in two adult male patients, aged 52 and 70 years, who were diagnosed histologically on surgical resection specimens. A comprehensive review of the literature has also been performed with a focus on survival data. Microscopically, the tumors presented herein were composed of relatively small rounded cells with a trabecular or nesting pattern. Both cases were diffusely immunopositive for chromogranin and synaptophysin, and one of them was also focally reactive with somatostatin and pancreatic polypeptide. There was no expression in any of these tumors of thyroid transcription factor-1 (TTF-1), gastrin, insulin, glucagon, vasoactive intestinal peptide (VIP) and prolactin. The tumor showed transmural invasion in both cases, with lymph node metastasis and subcapsular liver tissue infiltration in one. Both patients are alive with no evidence of disease 41 months and 59 months, respectively, after surgery. Despite being extremely uncommon, with only 70 cases reported to date, carcinoids should be included in the differential diagnosis of EHBD tumors. This study emphasizes the necessity of complete surgical resection as the gold standard treatment for these lesions, and the importance of a correct pathologic diagnosis for prognostic implications.