Prenatal ultrasound diagnosis of a rare morgagni hernia: a case report

Morgagni hernia is a rare type of congenital diaphragmatic hernia, and its prenatal diagnosis by ultrasound is extremely challenging, especially when combined with massive pericardial effusion, as it can be easily confused with other diaphragmatic hernias. This article reports a case of fetal Morgagni hernia definitively diagnosed by serial prenatal ultrasound and magnetic resonance imaging, followed by successful intrauterine pericardial drainage and postnatal surgical correction. It aims to emphasize the importance of standardized imaging follow-up for prenatal identification and perinatal management of this condition. A 28-year-old primigravida with no family history of genetic disorders underwent prenatal ultrasound at an outside hospital at 22 weeks of gestation, which revealed massive fetal pleural effusion, borderline normal width of the left lateral ventricle, and growth parameters below the 2.5th percentile for gestational age. At 27 weeks of gestation, she was referred to our hospital. Ultrasound and magnetic resonance imaging demonstrated a retrosternal liver herniation (Morgagni hernia) accompanied by massive pericardial effusion (range 48 mm × 28 mm). The lungs were compressed, but the lung-to-head ratio was 1.53, indicating acceptable lung development. After family consent, successful intrauterine pericardial drainage was performed at an outside hospital, with significant improvement in lung expansion observed 4 weeks post-procedure. A male infant weighing 2400 g was delivered by cesarean section at 39⁺ weeks of gestation. Postnatal imaging confirmed the Morgagni hernia, and on the second day after birth, diaphragmatic herniorrhaphy was performed, during which the herniated liver was reduced and the diaphragmatic defect was sutured. The infant recovered well after surgery. This case demonstrates the value of serial prenatal ultrasound combined with magnetic resonance imaging for the accurate diagnosis of Morgagni hernia with pericardial effusion. It also confirms that intrauterine pericardial drainage, when lung development is acceptable, can effectively relieve fetal lung compression and create favorable conditions for postnatal surgical correction, reflecting the positive impact of integrated prenatal–postnatal management on the prognosis of this rare diaphragmatic hernia.