Case Report: Metastatic Carcinoid as an Incidental Finding on Colonoscopy with Terminal Ileum Intubation

Abstract

Purpose: Case Presentation: A 67 year old Caucasian female underwent a routine screening colonoscopy which revealed normal mucosa. Upon intubation into the terminal ileum, a well circumscribed round submucosal lesion 2.0×2.0×2.0 cm was noted in the terminal ileum, 10 cm from the ileocecal valve. Biopsies of the tumor revealed cells that stained with Chromaffin, consistent with carcinoid tumor. The patient proceeded to laparatomy and underwent segmental resection of the tumor and mesenteric lymph node excision. A complete inspection of the bowel revealed no synchronous neoplasms. Histopathology of the tumor revealed 7/14 lymph nodes positive for metastasis. Our patient had no symptoms of carcinoid syndrome as there was no liver involvement. Discussion: Review of the literature reveals that small bowel carcinoids are typically asymptomatic until late in disease progression; few will present with the carcinoid syndrome. If symptomatic, it may present with abdominal pain or small bowel obstruction, typically presenting in the 6th to 7th decade. This may be due to mechanical effect of the tumor; cases of mesenteric angiopathy and intestinal infarction have been reported. One-third of all small bowel tumors are carcinoids, usually in the ileum within 60 cm of ileocecal valve, are often multiple (16-34%), and may be associated with other bowel tumors. Small bowel carcinoids also have a high tendency to metastasize compared to appendicle or colonic carcinoids. The incidence significantly increases if the tumor is more than one centimeter, but may still have metastasis at less than 1 cm, unlike appendicle carcinoids. A three-decade analysis of 3,911 small intestinal neuroendocrine tumors based on the NCI's SEER registry found that survival rates have not changed over the last thirty years. Overall, 5 year small bowel carcinoids are 55.4%, but drops to 36% in those with distant metastasis. Studies have shown that the incidence of small bowl cancers is increasing, with carcinoid incidence increasing 4-fold from 1985-2005. This patient was discovered when there was only lymph node involvement without distant metastasis to liver, lung, or bone. Subsequently her 5 year survival prognosis is 19.6% greater than if her disease had been discovered later with further metastatic involvement. This lends support to the importance of terminal ileum intubation on routine screening colonscopy to reduce the morbidity and mortality of small bowel carcinoid.