In two autistic subjects, there was a several-fold local increase in the thickness of the subependymal cell layer. Numerous subependymal nodules were found within a pathologically thickened subependymal cell layer, in the wall of the occipital horn of the lateral ventricle of a 7-year-old male, which reflects a subependymal nodular dysplasia (Fig. 1a–e). Nodules occupied 13.3 mm of the caudal portion of the occipital horn of the lateral ventricle. The diameter of round/oval nodules varied in size from 285 to 3,310 μm. While the smallest nodules were dispersed within the subependymal cell layer, the large nodules expanded partially into the white matter, and partially into the lumen of the ventricles and were detectable on MRI (Fig. 1a) and CV-stained histological sections (Fig. 1b, c). The effect was narrowing of the ventricle and the tuberous appearance of the ventricular wall. There were large tubers that contained dysplastic neurons with a partially modified morphology of pyramidal, multipolar or bipolar large neurons (Fig. 1d) and irregularly shaped medium and small neurons. Neurons in the small nodules were small and poorly differentiated (Fig. 1e).
