Prenatal diagnosis of isolated anorectal atresia with colonic perforation.

We report here a case of prenatal diagnosis of isolated anorectal atresia with intrauterine colonic perforation at 34 weeks of gestation, characterized by the presence of a bilobed cystic pelvic mass with a V-shape appearance separated from the bladder with changing features during observation. Mild ascites was also visualized. Other structures were normal on detailed ultrasound. The patient had spontaneously delivered a male infant weighing 2,100 g at 34 weeks of gestation. The infant died one day after birth, before surgical correction secondary to respiratory distress syndrome. Autopsy revealed isolated anorectal atresia, and high (supraelevator) lesions. In conclusion, the findings of bilobed cystic pelvic mass with a V-shape were useful to diagnose anorectal atresia in this case. Prenatal ultrasound can facilitate early diagnosis and treatment.