[Appendix vermiformis duplex--a rare surprise].

Duplication of the vermiform appendix is extremely rare. It is found in only 1/25.000 patients (0.004%) operated on for acute appendicitis. A 60-year-old male patient was hospitalized for a peridiverticular sigmoid abscess without signs of a free abdominal perforation and an abscess cavity in the small pelvis. A Hartmann's resection and an appendectomy (the vermiform appendix was part of the abscess wall) were performed. The pathology report described an external appendicitis. After 3 months, the intestine was successfully reanastomosed. During mobilisation of the coecum, a second retrocoecal vermiform appendix was surprisingly found. Because of signs of a chronic appendicitis a second resection was performed. Although the diagnosis of an appendix duplex is a rarity, surgeons should be aware of the possibility, especially when clinical signs and symptoms point to appendicitis, although at laparotomy the appendix looks normal. A routine exploration for a second appendix is definitely not indicated because of the rarity and the increased complication rate.