S3780 Adult Intussusception: Two Cases Highlighting Diverse Etiologies and Management Approaches

Introduction: Adult intussusception is a rare clinical entity. Unlike pediatric intussusception, adult cases are typically secondary to an underlying pathologic lesion, with malignancy being the leading cause in colonic intussusception. Infectious etiologies, represent an important subset. We present 2 adult cases of intussusception and discuss the importance of endoscopic evaluation. Case Description/Methods: Case 1: 50-year-old man with no past medical history presented to the emergency department with a 4-month history of progressive left lower quadrant abdominal pain. Initially intermittent, the pain had become constant over recent weeks without associated gastrointestinal symptoms. computed tomography (CT) abdomen/pelvis demonstrated ileocecal intussusception. Subsequent colonoscopy revealed a large 80 mm × 50 mm polypoid, infiltrative lesion at the ileocecal valve with partial luminal occlusion. Histopathologic analysis confirmed moderately differentiated adenocarcinoma. Patient underwent right hemicolectomy and adjuvant chemotherapy. Case 2: A 30-year-old man presented with 3-day acute abdominal pain and watery diarrhea. CT showed pancolitis with hepatic flexure intussusception. HIV testing was negative. Stool studies revealed Salmonella. Colonoscopy successfully reduced the intussusception with water/air insufflation. Biopsy results showed colonic mucosa with chronic active colitis with cryptitis and crypt abscess formation. Patient was advised to follow up but was lost to follow up. Discussion: Adult intussusception differs fundamentally from pediatric cases, requiring comprehensive evaluation for underlying pathology. While malignancy is the most common cause, infectious etiologies—including opportunistic infections in HIV patients (Kaposi's sarcoma, cytomegalovirus colitis, lymphoma)—must be considered. Unlike pediatric management with pneumatic reduction, adult cases additionally mandates cancer screening and infectious workup, including HIV testing when appropriate. Conclusion: These cases illustrate the diagnostic spectrum of adult intussusception. They underscore the critical importance of maintaining a high index of suspicion and broad differential when adult intussusception is identified. Urgent colonoscopy and cross-sectional imaging are essential to exclude malignancy. Early recognition enables optimal outcomes through timely surgical intervention or targeted medical therapy.