Further observations of endothelial changes accompanying delayed radiation necrosis in the human brain

A 56-year-old woman, who had been given radiation therapy for a squamous cell carcinoma of the scalp, presented 4-1/2 years later with a delayed radiation necrosis in the right frontal region of the brain. The fine structure of the small vessels was investigated. The endothelium often showed extreme attenuation, sometimes resulting in the formation of fenestrae. Occasionally the endothelial cells were widely separated allowing direct contact between blood elements and the endothelial basal lamina. In the latter cases, thrombus formation could sometimes be detected. Other changes of the endothelium included increased numbers of tubular bodies, pinocytotic vesicles and surface infoldings. (auth.)