Ultrasonographic detection of intrauterine intussusception resulting in ileal atresia complicated by meconium peritonitis.

A neonate with ileal atresia (IA) complicated by meconium peritonitis (MP) whose prenatal ultrasonography (US) detected an intrauterine intussusception (IUI) is reported. Fetal ascites, dilated bowel loops, and abdominal calcifications were identified on serial US from 25 weeks of gestation. Intestinal loops with high echogenecity and a "target-like" appearance suggestive of IUI were detected in the right lower quadrant. The 2,680-g male was delivered vaginally at term and underwent a laparotomy. Fibrous adhesions and small calcifications were scattered throughout the peritoneal cavity. IA (interrupted type) was confirmed 17.0 cm cranial to the ileocecal valve (ICV). An ileo-ileal intussusception was also found between 16.5 cm and 9.0 cm cranial to the ICV. Partial resection of the ileum and an ileo-ileal anastomosis was performed. The postoperative course was uneventful. In this case, the pathological process of IUI resulting in IA and MP was demonstrated sonographically by identifying the "target-like" appearance in the fetus.