MRI evaluations of pituitary volume, and clinical and endocrine findings in 101 pituitary dwarfs with congenital idiopathic growth hormone deficiency (CIGHD) are reported from the Departments of Neuroradiology and Pediatrics, Scientific Institute H San Raffaele, Milan, Italy. Ectopia of the posterior pituitary (PPE) was discovered in 59 patients and pituitary volume was reduced. Pituitary hormone deficiency, breech delivery, and other congenital brain anomalies occurred more frequently in PPE patients than in the 42 with normal posterior pituitary except for a narrowed stalk. Associated anomalies included septo-optic dysplasia, with septum pellucidum agenesis and/or hypoplastic optic chiasm, corpus callosum dysgenesis, and basilar impression. A congenital defect involving the pituitary and hypothalamus would account for the MRI abnormalities and the clinico-endocrinological features of CIGHD patients. Breech delivery is the result of the midline brain anomaly, rather than the cause. The hypothesis of a perinatal traumatic transection of the pituitary stalk is contradicted by the findings in this study. 
COMMENT. Major brain midline anomalies, including holopros-encephaly, corpus callosum dysgenesis, and septo-optic dysplasia may be associated with hypothalamo-hypophyseal deficiency. Pituitary gland hypoplasia and ectopia, demonstrated by MRI in this and other studies of CIGHD patients, is not correlated with breech delivery, but is related to an anatomical defect in hypothalamic-pituitary structures.