[Early stage of a cloverleaf skull malformation].

Cloverleaf skull anomaly was diagnosed sonographically and in the fetogram, together with concomitant chondrodystrophy. This resulted in an indication for intentional abortion in the 29th week. Consequently, this rare form of skull monstrosity could be examined pathologico-anatomically for the first time in a very early stage of foetal development. Contrary to the widely held opinion that the reason for such hideous malformation is a hydrocephalus internus due to a deformation of the skull base, we found a practically negligible hydrocephalus, although the cloverleaf skull had already developed in a very marked manner. Hence, this case contradicts the generally adopted formal pathogenetic interpretation of cloverleaf skull monstrosity.