Neuropathology of the dentate nucleus in developmental disorders.

The dentate nucleus was examined histologically and immunohistochemically in 47 cases of nonprogressive developmental disorders. Neuronal loss and/or atrophy was observed in 13 cases, while mild neuronal lesions, characterized by dendritic swelling and/or the appearance of eosinophilic materials around the neurons, were exhibited in 20 cases. The former change was accompanied by diffuse central nervous system involvement, and the etiology was perinatal hypoxic ischemic encephalopathy, acute encephalopathy, and meningoencephalitis in most cases. On the other hand, most of the patients with kernicterus showed the latter change. Immunohistochemically, the mild neuronal lesions mimicking grumose, degeneration, described in some neurodegenerative diseases, seemed to reflect the changes of Purkinje cell terminals. It is suggested that secondary structural alteration of the dentate neurons in the absence of severe atrophy can occur in nonprogressive developmental disorders.