S6198 A Case of an Ileal Carcinoid Tumor Mimicking Inflammatory Bowel Disease

Introduction: We present a challenging case of a patient with chronic abdominal pain and diarrhea, whose initial results on colonoscopy and imaging suggested inflammatory bowel disease (IBD). However, the patient did not improve with a high dose of steroids, and the diagnosis was questioned. We present this case to show that malignancy, specifically carcinoid tumors, should be part of our differential diagnosis in patients with chronic abdominal pain and diarrhea, and findings on colonoscopy suggesting IBD when they do not respond initially to steroids. Case Description/Methods: A man individual of 66 years old with personal medical history of hypertension, who has lived in the Philippines for more than 2 years, presented with 5 months of abdominal pain, diarrhea, and weight loss. Computed tomography scan of abdomen and pelvis revealed thickening of the small bowel wall, close to the terminal ileum, and colitis. Colonoscopy showed multiple ulcerations on the cecum and pathology showed chronic active colitis with cryptitis, crypt abscesses. There was a high suspicion of Crohn’s disease, and a high dose of steroids was started, but the patient did not respond after 7 days of treatment. Computed tomography angiography of abdomen and pelvis showed thickening of several loops of distal small bowel within the pelvis and abnormal soft tissue densities in the mesentery, but no changes on blood vessels. However, due to a lack of improvement, other options were considered, such as tuberculosis. To rule out intestinal tuberculosis, surgical biopsy of large mesenteric lymph nodes noted in the right pelvis was planned. Diagnostic laparoscopy revealed dead, nonviable ileum and right colon. This was an unexpected intraoperative finding prompting exploratory laparotomy, extended right hemicolectomy with ileal resection for Ischemic bowel secondary to suspected carcinoid tumor. Pathology confirmed a small bowel well-differentiated neuroendocrine tumor. Patient developed postoperative ileus but ultimately was discharged in good condition. Discussion: Ileal carcinoid tumors are rare, but they may be misdiagnosed as Crohn's disease. Previous studies have reported that approximately 2.3% of patients with ileal carcinoid were initially diagnosed and treated as IBD. The presence of disease refractory to medical therapy, including steroids, should alert clinicians to this possible diagnosis. Obtaining urinary 5-HIAA levels or exploring the option of early biopsy of any suspicious and feasible tissue (lymph node) or mass-like lesion should be considered.