CONICET | Buscador de Institutos y Recursos Humanos

Background: Cerebellar destructive lesions in preterm neonates end indisruptive processes if survival is long enough.Materials and methods: We analyzed the gross and histologic findingsof cerebellar hemispheres in 111 preterm neonates (27-35 weeksgestational age, 1-41 days) using an injury assessment scale. Astrocytesand microglia were studied immunohistochemically through a scoringsystem based on recognized classifications published elsewhere.Those data were statistically compared with each other as well as withtime-related factors (postnatal and gestational age), brain findings, andclinical data.Results: Two types of lesions were found: a) destruction (cell death,inflammation, infarct, hemorrhage), headed by astrocytic and microglialreaction in the internal granular layer and white matter; andb) disruption/underdevelopment (alterations in cerebellar weight andmorphometry of the cerebellar cortical strata). Both processes weredepicted by four lesion patterns. Initial destruction followed by disruptionwas frequently suspected in cases showing images of destruction,immature cortical mantles and a long survival. Congenital disruptionwith superimposed destruction was also considered in a few cases.Immunohistochemical studies revealed a positive correlation betweenastrocytosis/microgliosis, time-related factors, lesion patterns, andcerebral findings.Conclusions. Early changes were mild and not specific. In cases of longsurvival time, spatial-temporal regulated events beginning with destructiveinjuries (internal granular layer and white matter), and ending withdisruptive disturbances (cortical layers) were operative. Although lesionpatterns correlated well with immunohistochemistry patterns, cerebralfindings, and to some extent with perinatal data, a specific cause-effectrelation between type of injury and histopathology could not be found