CT findings in an alobar holoprosencephaly associated with Dandy-Walker's cyst.

Holoprosencephaly is a malformation of the brain due to a disturbance of the growth of the prosencephalon during the third cerebral vesicle phase of early fetal life. It is an anomaly of the prosencephalon with a single ventricle associated with malformation of the telencephalon and diencephalon. According to the degree of the malformation, this anomalad is classified into three types (DeMyer, W, Zeman, W. et al, 1964 ; DeMyer W, 1971.) : 1) alobar holoprosencephaly in which there is no formation of the cerebral hemispheres, 2) semilobar holoprosencephaly in which the formation is partial, and 3) lobar holoprosencephaly in which the formation is complete. In this paper, the authors describe neuroradiological features of the alobar holoprosencephaly with possible association of Dandy-Walker's cyst that has recently been encountred.