Congenital intrapericardial diaphragmatic hernia associated with atrial septal defect in a 3-year-old child: a case report

Congenital intrapericardial diaphragmatic hernia (CIPDH) is an extremely rare form of diaphragmatic hernia, in which abdominal contents herniate into the pericardial cavity. Due to its rarity and nonspecific clinical presentation, CIPDH is often misdiagnosed, particularly in settings with limited access to advanced imaging. A 3-year-old boy, born at term without neonatal symptoms, was referred to us for an atrial septal defect (ASD) closure, which was detected after an episode of pneumonia. Chest x-ray revealed cardiomegaly and bowel loops in the mediastinum. Echocardiography showed a 14 mm ASD (Qp:Qs = 3.1:1) with trivial pericardial effusion. A Morgagni hernia was suspected. The patient was scheduled for an elective ASD closure and simultaneous repair of the Morgagni hernia. The operation was done through a median sternotomy. The anterior side of the diaphragm was intact, and no Morgagni hernia was found. Once the pericardium was opened, we found the transverse colon herniated into the pericardial space. There was a 3 × 5 cm pericardial/diaphragmatic defect. We reduced the colon easily and closed the defect primarily with interrupted stitches of non-reabsorbable material. We then closed the ASD on cardiopulmonary bypass. The patient recovered uneventfully and remains well at 3 months of follow-up. Congenital intrapericardial diaphragmatic hernia should be considered in patients who have a preliminary diagnosis of an anterior (Morgagni) diaphragmatic hernia. • A rare case of CIPDH associated with ASD was diagnosed intraoperatively. • The herniated colon mimicked a Morgagni hernia on preoperative imaging. • Pericardiotomy revealed the true diagnosis during elective sternotomy.