Histopathological study on a case of idiocy--morphological mechanism of idiocy appearance.

A male, aged 42, had idiocy without any somatic or neurological signs. In laboratory examination, no abnormal finding could be observed. Brain weight was 1,330 g. and no abnormal finding was observed macroscopically. Histopathologically, gross changes were not observed, however, many nerve cells contained a lot of lipofuscin granules in the cytoplasms for the patient's age. Some astrocytes in the cerebral cortex contained homogenous amorphous inclusion bodies in their cytoplasms. From these findings, it was speculated that the change of astrocyte may play an important role in causing mental deficiency.