The scimitar syndrome: report of two cases of anomalous venous return from a hypoplastic right lung to the inferior vena cava.

An unusual association of malformations of the right lung was observed in two patients, and 36 similar cases were briefly reviewed. Findings included: (1) anomalous return of the right pulmonary veins, via a common channel, to the inferior vena cava, giving a typical radiological picture; (2) hypoplasia or absence of two major bronchi on the right side; (3) absence of the right pulmonary artery in one patient and hypoplasia in the other; (4) secondary dextroposition of the heart; (5) presence of a left-to-right shunt, through this abnormal circulation, varying from very small in one patient to more than 30% of the pulmonary blood flow in the other. When found together, these anomalies constitute a specific entity, the scimitar syndrome.