AbstractWe report the rare case of a giant low-grade appendiceal mucinous neoplasm (LAMN), presenting as ileocecal intussusception. An 80-year-old woman presented in the emergency department of our institution with progressively worsening diffuse abdominal pain during the last 24 h. A CT scan revealed a giant abdominal mass (98.7 × 127.3 × 107.6 mm) with air-fluid level and imaging characteristics of ileocecal intussusception. An emergency exploratory laparotomy was performed, and a well-circumscribed cystic mass deriving from the appendix was found. A right hemicolectomy was performed, and the histopathological examination confirmed the diagnosis of LAMN. This report aims to raise awareness among surgeons and radiologists, about LAMNs as a differential diagnosis of right iliac fossa masses presenting as acute abdomen.