Right aortic arch, isolated left common carotid and left subclavian arteries, and subclavian steal syndrome: a variant of polysplenia syndrome.

Congenital subclavian steal may result from various anomalies of the aortic arch. The most common predisposing type is the right aortic arch with an isolated left subclavian artery arising from a left ductus arteriosus. A rare variant includes isolation of the left common carotid as well as the left subclavian arteries. The case of an infant with polysplenia--F-anisosplenia syndrome and this rare variant of congenital left subclavian steal is presented. This anomalous constellation has been heretofore unreported and illustrates a new situs abnormality that may complicate the polysplenia syndrome.