Neuroendocrine Tumor of the Gallbladder, a Rare Incidental Finding.

BACKGROUND

Neuroendocrine tumors are a rare finding in the gallbladder. The incidence of this entity in the gallbladder is roughly 1.13 cases per 100,000 in the US, with a steady increase in the last decade. Gallbladder neuroendocrine tumors are generally asymptomatic; the majority of cases have been reported as incidental findings in specimens, resected due to secondary symptomatology, such as chronic cholecystitis. Treatment strategies are limited, in part due to the often advanced stage in which this disease presents. Furthermore, there is a restricted utility of diagnostic tools for early detection; these factors contribute to the poor prognosis of this disease process.

CASE SUMMARY: We describe a case of a gallbladder carcinoid tumor, incidentally found in a 78-year-old male patient who presented to the emergency room complaining of chronic intermittent right upper quadrant pain, accompanied by nausea and vomiting. A positive murphy sign was elicited on physical examination, which was otherwise unremarkable. An abdominal ultrasound showed an otherwise normal-appearing gallbladder except for a "floating polyp" with no suspicious radiologic features. A diagnosis of chronic cholecystitis was presumed, and the patient was taken to the operative room for laparoscopic cholecystectomy. Microscopic evaluation of the gallbladder specimen yielded a diagnosis of a well-differentiated neuroendocrine tumor and complex cholesterol polyps, in a setting of chronic cholecystitis.

CONCLUSIONS

Neuroendocrine tumors of the gallbladder, a rare entity, are generally asymptomatic, with most cases diagnosed incidentally in gallbladder specimen resected for reasons other than suspected malignancy. Chronic inflammatory processes are seen to be related to the development of metaplasia and possibly the development of tumors of the neuroendocrine lineage. Based on a review of literature, we have found that no specific treatment approach, beyond surgical resection, is in place to manage patients with this condition. Formation of an expert committee to review and discuss guidelines for appropriate clinical monitoring, as well as consideration of a multi-site prospective registry is suggested.