A rare case of congenital appendiceal duplication complicated by an appendiceal-sigmoid fistula: A case report.

INTRODUCTION: Duplication of the appendix is a rare congenital anomaly, occurring in approximately 0.004 % to 0.009 % of the population. In contrast, appendiceal-sigmoid fistulas are uncommon acquired conditions, usually associated with chronic inflammation or neoplastic processes. To our knowledge, the coexistence of these two entities has not been previously reported.

CASE PRESENTATION: A 26-year-old female presented with a one-month history of right lower quadrant abdominal pain, loss of appetite, and low-grade fever. Imaging findings initially suggested chronic appendicitis. During exploratory laparotomy, a Type A appendiceal duplication was discovered, with one of the appendices forming a fistulous connection to the sigmoid colon. Surgical treatment involved appendectomy, excision of the fistula, and primary repair of the colonic defect. Histopathological examination confirmed the diagnosis of duplicated appendix with chronic inflammatory changes. The patient had an uneventful postoperative recovery.

DISCUSSION: Appendiceal duplication typically remains an incidental finding, rarely causing clinical symptoms. The coexistence of appendiceal duplication and sigmoid fistula formation haven't been previously reported. Diagnosis can be challenging due to the limitations of preoperative imaging in identifying these anomalies. Therefore, surgical exploration remains crucial, particularly in symptomatic patients, to manage symptoms and prevent potential complications.

CONCLUSION: Clinicians should maintain a high index of suspicion for rare congenital anomalies like appendiceal duplication in patients who present with atypical symptoms of appendicitis.