FIG 1. Reformatted T1-weighted (fast spoiled gradient-echo) midsagittal and tilted coronal view MR images of three patients show the range of hypothalamic hamartoma sizes and their locations with respect to regions of the hypothalamus. The smaller lesion (A) is wholly intraventricular and confined to the mammillary region, without encroaching onto the tuber cinereum. The larger lesion (C) extends to the lamina terminalis in the preoptic region, abuts the optic chiasm, and displaces the pituitary stalk. Two hamartomas (A,C) are slightly hypointense relative to cortical and deep gray matter.