To search for the presence of morphostructural abnormalities of the hypothalamus-pituitary region in growth hormone deficient (GHD) children magnetic resonance imaging (MRI) was performed in 30 GHD patients (age 10.09 +/- 3.5 years) and in 15 healthy age-matched controls. MRI demonstrated a significantly small sella and pituitary volume compared to controls and normal literatures values. In 20 patients the structures were extremely small and an abnormal development of the pituitary stalk was observed, and in 18 of these patients the bright spot indicating the neurohypophysis was dislocated to the distal part of the maldeveloped stalk, although these children had a normal fluid balance. From a functional point of view hypothalamus and pituitary defects were equally distributed between the two morphological groups. The patients with multiple endocrine defects had the smallest pituitary volume and abnormal stalk. A possible pathogenetic role of perinatal trauma or dysembryogenic events are discussed. A careful follow up of patients with isolated GHD presenting MRI abnormalities of the pituitary is suggested for the possible evolution in panhypopituitarism.