Right-sided diaphragmatic hernia associated with superior vena cava syndrome.

The term "hydrops fetalis" denotes generalized fetal edema, a condition that differs from localized edema confined to head, extremities, or body cavities. This report illustrates a case of right-sided diaphragmatic hernia associated with severe edema of the head, polyhydramnios, small hydrothorax, and ascites with an antenatal diagnosis of hydrops fetalis. At autopsy, edema was confined to the head and neck and the peritoneal sac. The mechanisms responsible for these forms of localized edema were obstruction of the superior vena cava and hepatic veins, respectively. Localized fetal edema may be confused with hydrops fetalis. Fetal edema of the head and neck may result from obstruction of the superior vena cava by abnormal mediastinal structures.