Teaching Case

The boy presented with poor feeding, dyspnoea and abdominal discomfort.

22 days neonate presented with poor feeding, cyanosis, dyspnoea, cough, wheeze and abdominal discomfort. The boy was the product of a normal pregnancy and delivery. A chest x-ray showed a markedly enlarged cardiac silhouette, there was a soft tissue mass adjacent to the right atrium of the heart. Contrast-enhanced CT showed a right sided diaphragmatic hernia, with herniation of the left lobe of the liver that dorsally displaced the heart. There was abnormal large left lobe of the liver (8.4x3.8 cm), which occupied most of the abdominal cavity and displaced the gastric fundus downward. An enlarged spleen 7x4.2 cm that extended downwards to the pelvic rim and displaced the left kidney. Multiple triangular parenchymal non-enhancing lesions were seen within the periphery of the left lobe of the liver and spleen. There was absence of bifurcation of the portal vein. The main portal vein flowed away from the liver directly through a large vessel (patent ductus venosus) connecting the portal vein and the extrahepatic inferior vena cava. Intrahepatic portal branches were extremely small. The ductus venosus was approximately 1 cm in diameter and 2.5 cm in length. The low-attenuation area was seen around the ductus venosus. A left hepatic vein originated from two anomalous branches on the anterior surfaces of the left lobe, and connected directly to inferior vena cava. The hepatic artery arises from the aorta at the level of superior mesenteric artery.

The Morgagni hernia is located posterolateral to the sternum at the site of the internal mammary artery. This hernia usually occurs on the right side but may occur on the left or in the midline; it has also been described as retrosternal, parasternal, substernal, and subcostosternal [1]. The Morgagni hernia is rare in children, representing 1%-6% of all types of congenital diaphragmatic hernia. It is usually asymptomatic and discovered accidentally, or if symptomatic it produces variable nonspecific symptoms which include respiratory or vague gastrointestinal symptoms, and because of this the diagnosis is usually delayed [1]. The anterior Morgagni hernia may occur as an isolated defect or in association with other congenital anomalies. CDH can occur as part of a multiple malformation syndrome in up to 40% of infants, principally with cardiovascular,genitourinary,and gastrointestinal malformations. The ductus venosus, one of three essential shunts existing in the normal fetal circulation, is meant to allow the oxygenated blood from the placenta to bypass the liver and enter the right atrium directly. The ductus venosus in healthy neonates closes after birth later than the ductus arteriosus and usually before the 18th day [2]. A congenital shunt usually occurs as a single abnormal blood vessel that is a remnant of normal embryonic development. These shunts are defined as intra-hepatic or extra-hepatic depending on the location of the blood vessel in relation to the liver. Patency of the ductus venosus is a rare occurrence and represents either a primary developmental abnormality or a secondary state attributable to established liver cell failure [3]. The diagnosis of this portocaval anastomosis in infants is often made by ultrasound. The prenatal diagnosis of the right-sided diaphragmal defects can be extremely difficult because the liver is usually the only organ herniated into the chest, and the liver and lung have a similar echogenicity when visualized with US. Identification of the gallbladder may be helpful in these cases because it may be displaced superiorly or herniated into the chest. In radiographs, the foramen of Morgagni hernia appears as a homogenous mass in the right cardiophrenic angle [4]. When the hernia contains bowel, the diagnosis can usually be made by radiographs and barium studies [5]. CT is useful to determine that the paracardiac mass has fat density [4]. The differential diagnosis of a fat density mass in the right cardiophrenic angle includes pericardial fat pad, lipoma, and a Morgagni hernia containing omentum, or liver. MRI has also been used successfully in establishing the diagnosis of foramen of Morgagni hernia because this modality establishes the nature of the herniation mass, identifies hepatic vessels, and demonstrates the defect in the diaphragm, it can show the hepatic parenchyma and surrounding tissues [5]. MRA, with its wide field of view, has a particular advantage over Doppler US in depicting portosystemic vessels, patency, and anomalies. In this case multiple triangular parenchymal lesions within the periphery of the left lobe of the liver and spleen, it may be the result of infarction, or of lobation anomalies.