Rapidly grown congenital fetal immature gastric teratoma causing severe neonatal respiratory distress.

A pregnant woman in the mid-third trimester developed complications with enlarged fetal abdomen and polyhydramnios. Prenatal ultrasound visualized dilated bowel, intraperitoneal calcifications, ascites, hydroceles and polyhydramnios, giving the impression of meconium peritonitis. The fetal abdomen continued to increased in size, and maternal dyspnea due to polyhydramnios was aggravated. She underwent a cesarean section at 36 + 1 weeks' gestation. The delivery was followed by severe neonatal respiratory distress due to the huge mass in the abdomen. The tumor was successfully removed by emergency surgery and diagnosed as immature gastric teratoma. No other associated anomaly was found. The infant made a good progress after the operation.