Introduction: Appendiceal inversion occurs when the appendix is pulled into the lumen of the cecum, and can be an uncommon incidental finding on colonoscopy. When found, they may present as a diagnostic challenge to the endoscopist, as they may be mistaken as a colon polyp or even a neoplasm due to its appearance.
Case Description/Methods: A 75 year old woman with a history of hysterectomy, hypertension, and reported hemorrhoids presented to gastroenterology clinic for evaluation after being found to have a positive Cologuard test. She subsequently underwent colonoscopy, where she was found to have a large polypoid lesion protruding from the appendiceal orifice. Biopsies of the lesion revealed normal mucosa. Given the concerning appearance of the lesion despite normal biopsies, the patient was referred for repeat colonoscopy for endoscopic removal. Repeat endoscopy re-demonstrated a 5 by 10 millimeter non-bleeding, non-ulcerated, finger-like projection from the appendiceal orifice. Normal appearing mucosa of the lesion and its surroundings was observed under narrow band imaging. These findings were suggestive of an appendiceal inversion. The decision was made to not remove the lesion. The patient subsequently underwent CT imaging, where no significant underlying pathology was identified.
Discussion: At present, there are no definitive guidelines on the workup of suspected appendiceal inversions. Appendiceal inversion may occur iatrogenically after open appendectomy or they may be congenital. These are benign causes that would not require further intervention. However, they may be associated with conditions including endometriosis, adenomas, and neoplasms. Anecdotally, there have been reports of peritonitis or significant bleeding with removal of these lesions. A careful approach is thus imperative to prevent unnecessary complications.
A thorough surgical history should be taken as history of prior open appendectomy may increase suspicion for appendiceal inversion. Endoscopically, evaluation for surrounding inflammation and use of narrow band imaging to identify abnormal mucosa should be considered. Biopsy of the lesion may also be considered, but should be performed with caution. CT imaging may help exclude any underlying malignancy. Prior case reports have reported identification of mucinous neoplasms on CT following colonoscopy if the lesion cannot be determined to be an appendiceal inversion on endoscopy. In this patient, CT did not reveal any underlying malignancy.
