[Hypothalamic insufficiency following irradiation. Late, subacute and curable dementia]

A 31 year-old patient suffered from a subacute and major dementia, sixty months after whole brain irradiation with 54 grays for a pinealoma. Clinical features and biological investigations led to a diagnosis of hypothalamic insufficiency. A dramatic clinical recovery followed therapy with hydrocortisone and thyroxine. An hypothalamic radionecrosis and a vascular mechanism are presumed.