Background Neurenteric cysts are the association of an endodermal cyst with a vertebral dysplasia. This congenital malformation can be asymptomatic or manifest itself through respiratory signs due to airway compression.

Case report A male newborn, from normal vaginal delivery at 40 weeks of gestation, weighing 4000 g with Apgar score of 8 and 9 at 1 and 5 min was referred to the neonate intensive care unit. The clinical findings showed tachypnea, mild intercostals retraction and there was diminished air-entry on the right side. The chest X-ray showed vertebral anomalies in the midthoracic region, there was an hydric opacity occupying the 2:3 of the right side with deviation of the mediastinum to the left side. The CT scan of the chest revealed butterfly and hemi-vertebrae of the upper thorax. There was a large posterior mediastinal cystic mass partitioned by multiple septa on the inferior right side. On fifth day, the patient underwent a right thoracotomy. A large cystic mass attached to the oesophagus wall was exised, Histopathology favours the diagnosis of neurenteric cyst. Postoperatively outcomes were poor, the operation was complicated by bilateral chylothorax diagnosed on 10 th post-operative day and increasing oxygen needs. The newborn died on the 16 th postoperative day in a severe sepsis.

Conlusion Antenatal diagnosis of this malformation is not easy but possible. In post-natal, the radiological approach based on chest x-ray and CT scan, is helpful for establishing the diagnosis and lead to a prompt curative surgery.