Cor biloculare and associated malformations.

We report the clinical and autopsy findings of four unusual cases of the rate entity, cor biloculare, collected within a 4-year period. The cases are interesting for (1) the striking similarity of the associated anomalies, in contrast within the diversity of associated anomalies reported before; (2) the greater incidence of anomalous pulmonary and systemic venous return, pulmonic valve malformations and visceral heterotaxia than reported before; and (3) the normal, full-term, uncomplicated pregnancies. Family and gestational histories were unrevealing. All four cases had severe pulmonic valve malformations, pulmonary artery atresia, and visceral heterotaxia. Three of the four had anomalous pulmonary venous drainage and the fourth had anomalous systemic venous drainage. All four cases had polysplenia or asplenia. Correlating these associated anomalies with stages of embryonic development and with various studies of altered embryonic blood flow, suggests an etiologic role for altered blood flow in the development of this complex malformation.