Right-sided diaphragmatic eventration: a rare cause of non-immune hydrops fetalis

We report 2 cases of non-immune hydrops fetalis (NIHF) in which autopsy findings revealed an association with right-sided congenital diaphragmatic eventration (CDE). Both patients born at 30 weeks of gestation presented with severe generalized skin oedema, pleural effusions and ascites. They both died shortly after birth of cardiorespiratory insufficiency due to lung hypoplasia and low output heart failure. The right thoracic cavity was filled with the membranous but intact right diaphragm covering the herniated visceral organs including parts of the liver, small bowel and colon surrounded by voluminous ascites. In similar fashion to the situation seen in congenital diaphragmatic hernia (CDH), the displaced visceral organs led to impaired lung growth resulting in important lung hypoplasia and obstructed venous return. Extravascular liquid accumulation was probably further aggravated by hypoproteinaemia secondary to liver dysfunction resulting from the venous congestion and cardiac failure. In summary, CDE is a rare condition resulting from impaired ingrowth of muscle fibres into the diaphragm during the first trimester. Prenatal differentiation of CDE from CDH is a real challenge. The association of CDE and NIHF has not been previously described.