Horseshoe appendix: A case report and literature review.

Rationale: Horseshoe appendix is 1 of the rarest types of duplex appendix characterized by 1 appendix having 2 openings at the cecum. Clinically, it is extremely rare and is detected incidentally at surgery. Therefore, accurate and timely diagnosis is important for enhanced prognosis, treatment planning, and optimizing patient outcomes. This case report presents the first case of horseshoe appendix in France.

Patient Concerns: A French 15-year-old boy, presented to the emergency department with pain in the right iliac fossa that had been worsening for 4 days. Considering his symptoms, abdominal ultrasound, radiological examination, and computed tomography (CT) scan results, an acute appendix was suspected.

Diagnoses: Acute appendicitis (AA) with "horseshoe" type appendix.

Interventions: Surgical intervention with exploratory laparoscopy was performed immediately.

Outcomes: We found a heterogeneous image, partially fluid in the right iliac fossa, measuring approximately 16 × 9 mm, with inflammatory remodeling of the fat upon contact. The radiological examination concluded that complicated AA was suspected. Finally, the pathological report revealed acute suppurative appendicitis with peritoneal reaction.

Lessons: Horseshoe appendix is rare. Considering his symptoms, radiological examination, ultrasound, and CT scan results, an acute appendix was suspected. The patient was successfully treated using emergency surgery and antibiotics treatment thanks to further diagnosis via exploratory laparoscopy and pus microbial analysis.