The lesions found at autopsy in old infantile palsy cases are variable. The findings are for the most part porencephaly (more frequently pseudo-porencephaly, often mistaken for porencephaly), small and indurated convolutions, single or multilocular cysts and microgyria. There may be but little or no evidence of the initial cerebral lesion. In the great majority of cases, however, there is usually some non-development of the cerebral convolutions in which the whole hemisphere of the side involved often unequally participates.
The cerebellum of the same side or of the opposite side may also enter into the atrophy or non-development. The cerebellar lesion occurs on the same side if the pressure of the early lesion (hemorrhage) was great, or on the opposite side if the lesion resulted in large surface destruction or secondary atrophy of the hemisphere. There are, however, many varied changes present in individual cases; for instance, the calvarium and fossæ