title: Neuroendocrine tumors of the gallbladder: a case report and review of the literature.
abstract: BACKGROUND
  Primary gallbladder neuroendocrine tumors are extremely rare, representing 0.2% of all neuroendocrine tumors. The diagnosis is incidental in most cases.
  
  
  METHODS
  We describe the case of a 57-year-old Caucasian man who underwent laparoscopic cholecystectomy for the evaluation of a gallbladder polyp that had been incidentally detected by ultasonography. Histologically, his lesion was composed of monomorphic cells that contained small round nuclei and that were organized in small nodular, trabecular, and acinar structures. His cells were positive for chromogranin A and synaptophysin, and a diagnosis of "typical" carcinoid of the gallbladder was made. His post-operative computerized axial tomography, 111In-pentetreotide scintigraphy, and hormone-specific marker results were negative. He is disease-free 45 months after surgical treatment.
  
  
  CONCLUSIONS
  Characteristic pathological findings of the gallbladder neuroendocrine tumors predict the prognosis. Whereas classical carcinoids of the gallbladder only rarely have a metastatic or invasive phenotype, the "atypical" variants are more aggressive and are associated with a poorer prognosis. Given the difficulty in distinguishing between benign and malignant lesions in the pre-surgical setting, we tend to consider each polypoid-like lesion of the gallbladder to be a high-risk lesion if it is larger than 1 cm and, as a result, to emphasize the need for cholecystectomy in all cases, relying on the pathological and immunohistochemistry analyses for the final diagnosis.
authors.affiliation: Department of Radiology, Oncology and Human Pathology, Division of Oncology B, "Sapienza" University of Rome, Rome, Italy. Silvia.mezi@uniroma1.it.
authors.forename: Silvia
authors.initials: S
authors.lastname: Mezi
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Petrozza
authors.forename: Orazio
authors.initials: O
authors.lastname: Schillaci
authors.forename: Valentina
authors.initials: V
authors.lastname: La Torre
authors.forename: Barbara
authors.initials: B
authors.lastname: Cimadon
authors.forename: Martina
authors.initials: M
authors.lastname: Leopizzi
authors.forename: Errico
authors.initials: E
authors.lastname: Orsi
authors.forename: Filippo
authors.initials: F
authors.lastname: La Torre