Vascular alterations in delayed radiation necrosis of the brain. An electron microscopical study.

A 51-year-old woman who had been given cobalt therapy for nasopharyngeal carcinoma was seen three years later with a mass in the left frontotemporal region of the brain. Biopsy specimen of the lesion showed the classic features of delayed radiation necrosis on light microscopy. In addition, several blood vessels showed endothelial cell proliferation. Transmission electron microscopical study demonstrated numerous alterations of the endothelial cell, such as intraluminal infoldings of the plasma membrane, an increased amount of cytoplasmic organelles, and the frequent occurrence of tubular bodies in addition to degenerative and reactive changes in the neuropil.