The authors present the case of a prepubertal 14-year-old girl who was admitted for an acute abdominal pain, fever, and vomiting. She was in a poor general state, having recently suffered a weight loss of 5 kg. A plain abdominal x-ray disclosed signs of mechanical ileus. An abdominal ultrasound scan showed a normal uterus, a normal right-sided ovary, but no left ovary. An emergency laparoscopy found a normal uterus with complete absence of the left ovary and salpinx, the upper left dome of the uterus being smooth with no visible horn. The right ovary and salpinx were normal. Intestinal obstruction was caused by a strangulating cordlike structure of unclear origin. After converting to a laparotomy, we found an abnormal fallopian tube inserted in the left parieto-colic groove. The tube extended next on the lateral sigmoïd mesentery and wrapped itself around the ileum, provoking a local strangulation and an ischemic covered bowel perforation. The bowel perforation was treated by a segmental bowel resection. Careful dissection of the cordlike structure disclosed a true rudimentary fallopian tube with hypotrophic fimbriae and a small distal round structure containing ovarian tissue. These structures were removed entirely. A review of the literature on this rare situation is presented and discussed.