Case report: Acute appendicitis in appendix duplication

INTRODUCTION: Duplication of the appendix is a very rare presentation. According to the Cave–Wallbridge classification, there are three types of duplicate appendix. PRESENTATION OF CASE: A 43 year old female presented with classical symptoms of acute appendicitis, with unremarkable inflammatory markers. The diagnosis was confirmed on pre-operative computer tomography (CT). During laparoscopy two tubular structures were identified: one arising from the tenia libera of the caecum adjacent to the terminal ileum and one retrocaecally at the confluence of the teniae. Both structures were excised using a laparoscopic linear stapler. Histopathological analysis demonstrated the accessory structure to be a microscopically unremarkable blind-ended tubular structure. The other specimen demonstrated acute gangrenous inflammation of the appendix. The patient had an uneventful recovery and was discharged home the following day. DISCUSSION: Appendix duplication is rare; however, failure to recognise it in a patient with acute appendicitis could result in a retained source of sepsis, requiring subsequent re-exploration of the abdomen. The case presented here represents a Type B2 according to the Cave-Wallbridge classification and is the most susceptible to inadvertent error due to having appendixes in both typical and atypical anatomical locations. This case also highlights the probability of this diagnosis being missed on pre-operative CT. CONCLUSION: This case report presents a unique opportunity for surgical trainees to review intra-operative laparoscopic images of a duplicate appendix, both to allow them to recognise this pathology if encountered in the future, and to embed the importance of ruling it out with thorough intra-operative examination.