Inverted Appendix in a Patient With Weakness and Occult Bleeding.

Background: Appendiceal mucinous neoplasms (AMNs) are rare adenomatous primary tumors of the appendix. Although of low malignant potential, these neoplasms can cause serious potentially fatal complications such as bowel obstruction and pseudomyxoma peritonei, making prompt identification and removal of utmost importance. AMNs often present with nonspecific gastrointestinal symptoms or are asymptomatic and found incidentally. Case Presentation: A patient aged 72 years presented with generalized weakness and appeared on imaging to have acute appendicitis complicated by rupture. On colonoscopy, the patient was found to have an inverted appendix that after appendectomy was revealed to harbor a perforated low-grade AMN. Conclusions: Although AMNs are rare, physicians should still consider it when imaging suggests appendicitis. Having AMNs as part of the differential diagnosis is especially necessary in cases, such as this one, in which the patient has appendiceal inversion, is aged > 50 years, and has concurrent colorectal neoplasms.