AB183. SOH25_AB_179. When the appendix takes a detour: a rare case of adult intussusception into the cecum mimicking appendiceal mucocele

Background: Acute appendicitis is a common condition, with an incidence of 100 to 223 cases per 100,000 individuals annually. Accurate diagnosis relies on multiple modalities in conjunction with a thorough clinical examination. Imaging, particularly through computed tomography (CT), is highly sensitive in reliably determining the position of the appendix. It is not unusual for appendicitis to present in atypical ways or be masked as other intra-abdominal conditions, complicating the diagnosis. This report discusses a rare case of intussusception of the appendix into the cecum, highlighting an uncommon presentation.

Case Description: We report a case of a 51-year-old woman who experienced worsening abdominal pain, nausea, and early satiety over several months. Initial evaluation revealed microcytic anaemia and a smoking history of 25 pack-years. Imaging strongly suggested an appendiceal mucocele. A colonoscopy revealed a large caecal polyp originating from within the appendiceal orifice. A multidisciplinary team discussion recommended performing a diagnostic laparoscopy to further guide management. While conducting the laparoscopic surgery, a lump on the taenia coli obscured the view of the appendix, necessitating a partial cecectomy. Postoperative examination of the specimen confirmed intussusception of the appendix into the cecum, later verified by a pathologist.

Conclusions: This case highlights the significant diagnostic challenges linked to adult intussusception. Although CT scans and colonoscopy are vital in preoperative assessments, correctly identifying the underlying condition can be difficult. The laparoscopic approach has shown both safety and effectiveness in diagnosis and treatment. Prompt surgical intervention is crucial for resolving intussusception and treating appendicitis to prevent serious complications.

Keywords: Acute appendicitis; appendiceal mucocele; intussusception; laparoscopic surgery; case report