Diagnostic strategies in pediatric imaging.

Magnetic resonance imaging is the modality of choice to visualize the pituitary gland. In pituitary dwarfism with growth hormone deficiency, neuroimaging can be normal or can disclose abnormalities: (1) Tumors, mainly craniopharyngiomas. These benign tumors vary greatly in size and composition (calcifications, a cystic component in approximatively 80% of cases, typically with high signal intensity on T1-weighted images). (2) Classical midline malformations such as septo-optic dysplasia or corpus callosum agenesis. (3) Recently described minor malformations: pituitary hypoplasia, pituitary stalk aplasia, and translocation of the pituitary bright spot to the median eminence called an "ectopic' posterior lobe. All these malformations can be isolated or associated. (4) Pituitary adenomas (prolactinomas), which are not frequent in children.