[Acardiac malformation: ultrasonographic diagnosis. A case report]

Acardia is an extremely rare malformation which is seen in less than 1 per cent of monozygous twin pregnancies. Pathological aspects and etiopathogenic theories concerning this malformation are reviewed on the basis of a case diagnosed in utero at 24 weeks. The value of the antenatal diagnosis of this malformation is that of monitoring the progression of the pregnancy and predicting the fate of the healthy twin.