*    Department of Obstetrics and Gynecology, ARNAS Civico -  Palermo - Italy;
**   Department of Obstetrics and Gynecology, "V. Cervello" Hospital - Palermo - Italy.

A 28-year-old woman (G2,P0) presented at 30th week of pregnancy. Previous examinations were normal. Ultrasound investigation revealed diaphragmatic hernia with intrathoracic cystic mass. Echographic surveillance was done during the rest of pregnancy without any other signs of fetal problems. The patient delivered at 38th week of pregnancy by Caesarean section. The male baby weighted 3100 grams and underwent successful surgical operation where we found out that the cystic mass is actually peritoneal pseudocyst bulging into the thoracic cavity through a hole within diaphragm. Postoperative course was normal.

Transversal planes through thorax and sagittal plane done at 30 week of pregnancy, showing cystic mass located in left dorsolateral portion of the thorax.

Power Doppler shows the stream of the gastric content confined to interior of the stomach.

Videos show cystic mass inside the thorax. Border (two surfaces) between cyst and stomach can be seen. 

Pictures showing the peritoneal pseudocyst inside the thorax.

Pictures show the hole in the diaphragm with visible part of stomach (left) and drawing (right) shows the mechanism of formation of the peritoneal pseudocyst.