Porencephaly from periventricular intracerebral hemorrhage in a premature infant.

In two thirds of the premature infants who survived large periventricular intracerebral hemorrhage, a porencephalic cyst developed at the site of parenchymal hemorrhage. The porencephaly seems to develop as a result of local parenchymal destruction by the hemorrhage itself. These cysts can occur in the absence of posthemorrhagic hydrocephalus or increased intracranial pressure. Three of four infants who were observed for at least five months had lateralized motor deficit that corresponded to the cyst.