2596 Diagnosis of Terminal Ileum Carcinoid Tumor Despite Prior Screening Colonoscopies—Making the Case for Routine Terminal Ileoscopy During Colon Cancer Surveillance: A Case Report

Abstract

INTRODUCTION: The term carcinoid is generally applied to well-differentiated neuroendocrine tumors originating in the tubular digestive tract, lungs or rare primary sites. Small bowel neuroendocrine tumors may be asymptomatic at presentation and found incidentally. Among symptomatic patients, 40% experience abdominal pain as an initial symptom. The pain is usually vague, nonspecific and misconstrued to represent irritable bowel syndrome for years before a diagnosis is made. A diagnosis may be delayed, or even missed, due to terminal ileum visualization not being a routine part of screening colonoscopy, a result of the perceived difficulty of the maneuver. We present the case of a female patient who was diagnosed with carcinoid tumor only after she became symptomatic despite having routine colonoscopy screening prior. CASE DESCRIPTION/METHODS: A 74-year-old female without significant past medical history initially presented to clinic with complaints of non-specific abdominal pain and intermittent non-bloody diarrhea. Vital signs and physical exam were unremarkable. The patient subsequently underwent a colonoscopy, during which she was found to have inflamed ileal mucosa. Biopsy was taken and microscopic findings revealed a tumor composed of small uniform cells demonstrating a festoon growth pattern with ovoid nuclei. Immunoperoxidase staining revealed the tumor cells to be positive for pankeratin, chromogranin and synaptophysin, confirming a diagnosis of carcinoid tumor. Patient has since been referred for surgical evaluation. DISCUSSION: Due to the high amount of patients being screened, there is an urgency now more than ever to minimize colonoscope advancement and mucosal inspection time. As depicted in our case, patients may go through more than one surveillance colonoscopy with a missed diagnosis, particularly in the terminal ileum. This is especially a concern in asymptomatic patients with carcinoid tumors. Though evidence has shown improvement in colonic diagnoses, completion of colonoscopy by passage through the ileocecal valve is not yet routinely performed in screening colonoscopies. Difficulty in intubation of the valve as well as an anticipated increase in procedure time have become barriers in establishing this as a standard. With practice, ileoscopy may be highly achievable in routine colonoscopies. This will allow for a decrease in missed diagnoses, early detection and thus more treatable cases overall.