Diagnostic Challenge of Sequential Appendicitis in a Patient With Appendiceal Duplication: A Case Report

BACKGROUND Appendiceal duplication is an exceptionally rare congenital anomaly, with a reported prevalence of less than 0.003%, and remains poorly represented in the contemporary evidence-based surgical literature. Recent Cochrane reviews and PubMed-indexed meta-analyses (2024 onward) have refined diagnostic pathways and management strategies for acute appendicitis; however, congenital anatomical variants such as appendiceal duplication are largely excluded from these analyses. Among the described subtypes, type B2 duplication according to the Cave-Wallbridge classification is clinically significant due to the presence of 2 completely independent appendices arising from opposite teniae coli. This configuration carries a substantial risk of delayed diagnosis, missed intraoperative recognition, and sequential appendicitis, particularly in patients with a history of prior appendectomy. CASE REPORT A 33-year-old man with a previous open appendectomy and histopathological confirmation of acute appendicitis presented 3 years later with recurrent right lower quadrant pain and signs of localized peritonitis. Cross-sectional imaging demonstrated free intraperitoneal fluid but failed to identify a definitive etiology. Exploratory laparotomy revealed a second, previously unrecognized retrocecal appendix located along the omental tenia, consistent with type B2 appendiceal duplication, complicated by acute inflammation and perforation. A retrograde appendectomy was performed. Comparative histopathological analysis confirmed acute appendicitis in both specimens, establishing the diagnosis of sequential appendicitis secondary to appendiceal duplication. CONCLUSIONS Appendiceal duplication, although exceedingly rare, is a clinically relevant cause of recurrent abdominal pathology after appendectomy. Careful intraoperative inspection of the cecum and its teniae is essential to avoid missed diagnoses. Increased awareness and reporting of this anomaly are necessary to integrate rare anatomical variants into evidence-based surgical practice.