Inappropriate growth hormone release in the diencephalic syndrome of childhood: case report and 4 year endocrinological follow-up.

A boy with an astrocytoma in the anterior hypothalamic area and typical features of the diencephalic syndrome of childhood was followed with yearly endocrinological evaluation from 10 months of age until he was 5 1/2-years-old. Radiation therapy resulted in temporary clinical improvement. At the time of diagnosis height and bone age were advanced. Basal concentrations of growth hormone (GH) were markedly elevated and could only be partially suppressed by an oral glucose load. There was a paradoxical decline of GH levels following arginine-insulin infusion and an abnormal GH release with TRH administration. Abnormal GH response to the various stimuli persisted for 2 years after radiation therapy. Pituitary secretion of LH, FSH, TSH, prolactin and ACTH remained intact. The characteristic clinical features as well as the endocrinological findings remain unexplained.