S6161 Beyond the Scope: Terminal Ileum Adenocarcinoma Diagnosed After Failed Intubation

Introduction: Adenocarcinoma of the small bowel is a rare malignancy, representing less than 5% of all gastrointestinal cancers. Fewer than 20% of small bowel adenocarcinomas arise in the ileum, and the incidence is under 1 per million per year. Due to its anatomic location and nonspecific symptoms, ileal adenocarcinoma is frequently diagnosed at an advanced stage. We present a case of ileal adenocarcinoma causing partial small bowel obstruction, highlighting the diagnostic challenges at the ileocecal junction. Case Description/Methods: A 50-year-old man with a history of alcohol and tobacco use and prior appendectomy presented with diffuse abdominal pain, nausea, and intermittent vomiting. Physical examination showed mild abdominal tenderness. Laboratory evaluation was notable for normocytic anemia. Computed tomography of the abdomen revealed a segmental stricture of the terminal ileum, distal esophageal thickening, and mesenteric adenopathy. Esophagogastroduodenoscopy was unremarkable. Four days later, colonoscopy demonstrated a friable, near-obstructive lesion at the ileocecal valve with failure to intubate the terminal ileum due to severe narrowing. Biopsies revealed inflamed adenomatous epithelium with high-grade dysplasia. Due to persistent symptoms and high suspicion for malignancy, the patient underwent laparoscopic right hemicolectomy. Surgical pathology confirmed invasive adenocarcinoma of the terminal ileum with metastasis to regional lymph nodes (pT3N2), consistent with stage III disease. Discussion: This case illustrates the diagnostic difficulty of terminal ileal adenocarcinoma, particularly when lesions are not reachable by conventional endoscopy. Risk factors include hereditary polyposis syndromes, inflammatory bowel disease, celiac disease, and lifestyle exposures such as alcohol and tobacco use. Symptoms are typically vague, such as abdominal pain, obstruction, or anemia, delaying diagnosis. Cross-sectional imaging and timely surgical referral are critical when malignancy is suspected. With rising incidence rates, awareness of ileal adenocarcinoma must increase to enable earlier diagnosis and intervention, potentially improving outcomes.