S6162 A Gut-Twisting Tumor: Ileal Neuroendocrine Tumor Presenting as a Palpable Mass and Intussusception in an Adult

Introduction: Neuroendocrine tumors (NETs) of the small intestine are rarely identified on imaging and endoscopy. Patients present with nonspecific symptoms neoplasms including abdominal pain, nausea, and vomiting, and typically undergo several imaging studies and endoscopic evaluations prior to diagnosis. However, a physical examination may lead to prompt management, as in our patient. Identification of the NET on endoscopy is clinically significant due to its high malignant potential, and substantial risk of distant metastasis even when small. Case Description/Methods: A 47-year-old woman with a history of iron deficiency anemia and thyroid cancer status post thyroidectomy and radiation presented to the clinic with a 2 month history of episodic epigastric pain, early satiety, nausea, and emesis. There was no significant surgical, family, or social history. A physical exam revealed a palpable, hard mass in the lower abdomen. Computed tomography of the abdomen revealed a possible ileocolonic mass causing apparent ileocolonic intussusception, and an adjacent pathologically enlarged lymph node. Colonoscopy was performed revealing large friable, partially obstructing mass in the terminal ileum. Biopsies of the lesion demonstrated a focally ulcerated, well-differentiated neuroendocrine tumor. The patient initially underwent 1 distal ileal resection of the tumor, but on secondary review of the small bowel several 2-3 mm lesions were palpated near the previous anastomosis and additional resection was then performed, with subsequent side-to-side stapled anastomosis. Discussion: This case underscores a rare but significant presentation of ileal NET as a palpable abdominal mass and intussusception in an adult patient. While intussusception is uncommon beyond childhood, its presence in adults is often pathologic and indicates an underlying neoplasm. Given the propensity for mesenteric spread even in low-grade NETs, early recognition and diagnosis are key for proper staging and management. Small bowel NETs should be considered in adults with anemia or obstruction, and physical examination may lead to prompt imaging and diagnosis through endoscopic evaluation.