Hypothalamic hypopituitarism following external radiotherapy for tumours distant from the adenohypophysis.

Three cases of panhypopituitarism and five of isolated growth hormone deficiency which occurred following previous external irradiation of tumours distant from the adenohypophysis are described. The hypothalamic pituitary region received between 2800 and 12 000 rads in each case, 1-9 years before endocrine deficiency was recognized. Evidence is presented that the site of damage is in the region of the hypothalamus rather than the pituitary gland itself. Individuals treated with X-ray therapy in whom the hypothalamic-pituitary region is exposed to irradiation would appear to be at risk of developing some degree of delayed hypothalamic-pituitary dysfunction.