A 50-year-old woman with a history of hysterectomy for endometrial cancer in 2015 visited because of abdominal pain for 1 week and fever simultaneous with her third dose of the COVID-19 vaccine. Physical examination revealed a mobile mass in the right iliac fossa, and laboratory testing showed C-reactive protein at 3 mg/dL, with no further changes. Ultrasound results were consistent with an appendiceal inflammatory mass, and a CT scan revealed an appendicolith as likely cause. The patient was subjected to laparoscopy, which found inside the mass a metallic piece (dental prosthesis) that perforated the appendiceal lumen at the mid portion of the appendix. Appendectomy was completed and the patient was discharged on the third day post-procedure.