PERIAQUEDUCTAL MICRODYSPLASIA IN CHILDREN WITH CONGENITAL AQUEDUCTAL STENOSIS

The brainstems of children with aqueductal stenosis (AS) and controls were examined histologically and immunohistochemically. In the periaqu eductal area of children with AS, there was astrogliosis, loss of neur ons (tyrosine-hydroxylase (TH) reactivity) and decreased myelination ( myelin basic protein reactivity). In locus coeruleus, there was a decr eased neuronal cell density (TH-positive neurons) in those with AS. In other areas of the brainstem (medial reticular formation), there appe ared to be more TH and substance P reactive neurons. These alterations (dysplasia of slight degree) in neurons were more remarkable in child ren with AS with other identified brain anomalies than in those with o nly AS, judged by specific immunocytochemical identification of neuron s. The periaqueductal astrogliosis and delayed/insufficient myelinatio n suggest secondary damage to this region.