Complete appendiceal inversion with local high-grade intraepithelial neoplasia in an adult female: a case report

Background Appendiceal inversion with neoplasia in adults is an extremely rare event with a reported incidence of < 0.01%. Preoperative diagnosis is very important for surgical treatment; however, it is very difficult to be exact. Case presentation The patient was a 60-year-old woman with complaints of intermittent abdominal pain. Computed tomography and colonoscopy revealed a cecal mass, which was diagnosed as a tubulovillous adenoma in the preoperative colonoscopic biopsy. At surgery, the appendix was found to be completely inverted into the cecum. The cecum was partially resected, and surgical pathology examination confirmed a tubulovillous adenoma of the appendix with local high-grade intraepithelial neoplasia. Conclusions Although preoperative diagnosis of appendiceal inversion with neoplasia may be often difficult due to its non-specific symptoms, clinicians should consider this disease entity when they encounter an intraluminal protruding cecal mass without visualization of the normal appendix on CT and colonoscopy.