BACKGROUND Late-onset mesh infection after inguinal hernia repair is uncommon, and onset occurring years later is rare. Risk factors include field or implant contamination, host factors, such as diabetes and chronic steroids, and secondary fistulae with adjacent organs. CASE REPORT An 86-year-old man underwent right inguinal hernia repair with the Prolene Hernia System about 10 years earlier. He presented with right lower quadrant pain. Computed tomography (CT) showed an abscess tracking from the appendiceal tip to the right lower abdominal wall, suggesting mesh infection. Symptoms improved with conservative treatment, but purulent drainage from the right groin appeared after hospital discharge. Repeat CT identified a cecal mass; colonoscopy confirmed an appendiceal orifice tumor, pathologically an adenoma. Obstruction at the appendiceal orifice produced a fistula between the appendix and the abdominal wall, leading to delayed mesh infection. Planned laparoscopic ileocecal resection was performed. Intraoperatively, the appendiceal tip was densely adherent to the abdominal wall, and a portion of mesh was exposed intraperitoneally; no pus was encountered. Expecting control without explantation, we performed ileocecal resection with the mesh left in situ. Persistent groin drainage necessitated staged mesh removal: most of the implant was excised first, then a second operation removed the remainder with open drainage. Negative-pressure wound therapy achieved complete healing without recurrence. CONCLUSIONS This case highlights the management difficulty of mesh infection caused by an appendiceal fistula long after hernia repair. Failure to remove all mesh markedly increases the risk of recurrence and prolongs treatment; in this patient, incomplete initial removal likely lengthened the clinical course.