VM12 - Appendicitis Following Endoscopic Resection of a Peri-Appendiceal Polyp in a Patient with Concurrent Sigmoid Colon Cancer

Purpose/Background: Complex colorectal polyps are lesions whose size (>20mm), morphology (flat/bulky), extent (crossing two haustra folds or >1/3 lumen circumference), presence of scarring/fibrosis or location (IC valve, appendiceal orifice) make endoscopic resection technically challenging. Advanced endoscopic techniques such as endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and endoscopic full thickness resection (EFTR) are effective for removal of complex polyps and can spare patients with benign lesions morbidity of surgical resection. However, these techniques carry a higher risk of bleeding, perforation, and stricture than simple polypectomy. We present a case of appendicitis following EFTR that highlights the need to alternatively consider a combined endoscopic/laparoscopic approach for select patients.

Methods/Interventions: A 70-year-old woman underwent screening colonoscopy in March 2023 that identified a suspicious umbilicated lesion in the sigmoid colon and a polypoid lesion at the appendiceal orifice that could not be removed using forceps or snare techniques. Pathological analysis confirmed the sigmoid lesion was invasive adenocarcinoma. Subsequent colonoscopy by the advanced endoscopy team utilized a full thickness resection device (FTRD) to resect the appendiceal orifice polyp.

Staging CT scans ruled out metastatic disease but was notable for the presence of a metal clip at the base of the appendix, appendiceal distension of 1.8 cm without other associated findings of inflammation; read as “possible appendicitis or mucocele”. Three weeks after her procedure, she developed fever, nausea and vomiting and went to the emergency room. Labs demonstrated leukocytosis and CTAP showed appendiceal dilation to 2.5 cm with peri-appendiceal fat stranding without signs of perforation. After a risk/benefit discussion, she opted for medical management with a plan for delayed appendectomy at the time of her scheduled sigmoid colectomy. She was discharged home the following day after clinical improvement to complete the course of antibiotics.

Two weeks later, robotic-assisted sigmoidectomy and extended appendectomy was performed without complication. The presence of the endoscopic clip precluded division of the appendix at the base, so a stapler was used to divide across the cecum to include the entire appendix as well as a cuff of cecum. Care was taken to avoid injury or narrowing of the ileocecal valve. The appendix specimen included the endoscopic clip. The staple line was reinforced with a layer of vicryl sutures.

Results/Outcomes: The patient had an unremarkable post-operative course and was discharged home on post operative day 2. Surgical pathology demonstrated chronic appendicitis and no malignancy within the appendix. Sigmoid colon specimen was significant for 1/18 lymph nodes positive for metastatic disease (pT2N1). The patient is now undergoing adjuvant chemotherapy to complete treatment.

Conclusion/Discussion: Appendicitis following EFTR is a frequently reported complication, occurring in up to 17% of cases. Alternative approaches, such as combined endoscopic and laparoscopic surgery (CELS) and full-thickness laparo-endoscopic excision (FLEX) are highly effective techniques for peri-appendiceal polyps with lower risk of procedural complications in most cases. This case underscores the importance of interdisciplinary collaboration in the optimal management of complex colorectal polyps.