Cecal Polypoid Lesion Revealing an Invaginated Appendiceal Stump: A Case Report

Background: Appendiceal stump invagination is a rare cause of a cecal polypoid lesion that may closely mimic neoplastic lesions on colonoscopy, particularly in patients with a history of prior polypoid lesions resections. Recognizing this entity is essential to avoid unnecessary polypectomy or surgical intervention. Case Presentation: We report the case of a 63-year-old woman with a history of appendectomy and prior endoscopic submucosal dissection of a cecal laterally spreading tumor. During surveillance colonoscopy performed in 2026, a 15 mm non-inflammatory polypoid lesion was identified in the cecum. Given the patient's history, cecal polyp was initially suspected. However, narrow-band imaging demonstrated a smooth mucosal surface with preserved glandular and vascular architecture, without dysplastic features, leading to the diagnosis of an invaginated appendiceal stump rather than a true neoplastic polyp. Conclusion: This case illustrates that appendiceal stump invagination should be included in the differential diagnosis of cecal polypoid lesions, especially in patients with prior appendectomy or cecal surgery. Careful endoscopic evaluation can help differentiate this benign anatomic variant from true neoplasia and prevent inappropriate therapeutic procedures.