Persistent matrix cell nests in human cerebellar nuclei.

A histological study of the cerebella of 200 human infants ranging in age from 30 weeks gestation to 6 postnatal months disclosed in 42 per cent of the infants less than four months old the presence of embryonal cell nests in the deep cerebellar nuclei. Their incidence was highest in premature infants (72 per cent) with constant decrease up to 4 months of age. The occurrence of matrix nests in the cerebellar nuclei was without relation to any primary lethal disease except for trisomy syndromes, where large cerebellar heterotopias and persistent matrix cell nests were commonly associated with abnormal gyrification of the deep nuclei and with other developmental anomalies of the central nervous system. Matrix cell nests in the deep cerebellar nuclei which seem to dissolve by the 4th postnatal month, i. e. at the same time as the external granular cortical layer, are considered to be either normal or insignificant variations of normal development, probably related to retarded gyrification and myelination glia of the cerebellar nuclei. The causes for frequent association in trisomy and other malformation syndromes of disordered gyrification of cerebellar nuclei with persistence of large matrix nests are unknown.