PROGRESSIVE VISUAL FAILURE IN ACROMEGALY FOLLOWING EXTERNAL PITUITARY IRRADIATION

Four of 23 acromegalic patients selected for treatment with external megavoltage pituitary irradiation between 1961-1975 developed progressive visual failure. They had received megavoltage external irradiation through multiple portals from a 60Co unit over a period of 3 wk. Visual deterioration began 2 mo.-6 yr after irradiation. In 2 patients the optic nerves were explored. In both, post-mortem later confirmed radiation damage to the optic nerves and hypothalamus. In 1 case there was also necrosis of the right frontal lobe with necrosis and inflammation of the bone surrounding the pituitary fossa. In the 2 other patients, extensive clinical and neuroradiological investigation excluded the presence of a suprasellar mass as a cause for this visual failure and a clinical diagnosis of radiation necrosis was made.