Multicystic encephalopathy: review of eight cases with etiologic considerations.

Multicystic encephalomalacia (MCE) is a rare lesion that arises during the perinatal period. Although hypoxic-ischemic insults may be responsible for this lesion, recent evidence suggests that herpesviruses may represent another etiologic agent. To elucidate the pathogenesis of MCE, eight cases collected over a 34-year period were evaluated for destructive lesions in gray and white matter. Immunocytochemical methods, in situ hybridization and polymerase chain reaction (PCR) methodology were employed to search for herpes simplex viruses types 1 and 2 (HSV1 and HSV2), cytomegalovirus (CMV), varicella zoster virus (VZV), Epstein-Barr virus (EBV) and JC variant of papovavirus (JCV). Review of the clinical histories revealed that there had been a complicated labor and delivery in 6/7 cases. Neuropathological lesions consisted of extensive tissue destruction, neuronal loss and gliosis in hemispheric white matter, cerebral cortex, basal ganglia, thalamus, cerebellum and brainstem tegmentum. Only one case showed evidence of latent HSV infection by PCR. CMV, VZV, JCV and EBV were not detected. Arteriopathy was noted in one case. The widespread nature of the lesions and their association with perinatal ischemia suggest that severe hypoxia may be the more common etiology of MCE. Term infants appear especially susceptible to this type of cerebral damage.