EPENDYMAL ABNORMALITIES IN LISSENCEPHALY PACHYGYRIA

The ependyma was examined in eight children with neuroblast migratory disorders of diverse origin: three cases of lissencephaly type 1 with severe to mild degrees of agyria/pachygyria, four cases of lissencepha ly type 2 in Fukuyama muscular dystrophy and the Walker-Warburg syndro me, and one case of hemimegalencephalic pachygyria. Morphological and immunohistochemical abnormalities of the ependyma were strikingly simi lar in all. Discontinuities were disproportionate to the degree of ven triculomegaly. In some regions, the ependyma remained a pseudostratifi ed columnar epithelium, though basal processes were absent. The poles of the horns of the lateral ventricles were replaced by extensive hete rotopic ependymal rosettes. Rosettes and rows of ependyma also were in other subventricular sites. Subependymal nodules of large astrocytes and their processes bulged into the ventricular lumen after infancy. E pendymal cells did not express glial fibrillary acidic protein, but sh owed persistent expression of S-100 protein, cytokeratin CK-904 and so metimes vimentin long after these proteins normally disappear. An abno rmal ependyma in lissencephaly/pachygyria may contribute to disturbanc es in neuronogenesis, guidance of axonal projections and neuroblast mi grations: it may be a primary factor in pathogenesis.