Analysis of the histopathology of radiation myelopathy

An analysis of published histopathology reports of patients with radiation myelopathy was performed. Radiation lesions in the spinal cord were classified as primarily white matter parenchymal lesions (type 1), primarily vascular lesions (type 2), or a combination of vascular and white matter lesions (type 3). The presence or absence of a mononuclear inflammatory reaction was also noted. Type 1 and type 3 lesions had comparable latent periods, both significantly shorter than those observed for type 2 lesions. The anatomical level of the irradiation did not appear to influence the type of lesion. Inflammatory reaction was observed with greater frequency in type 3 lesions. For all types of lesions, the average latent periods in patients with inflammatory reactions were shorter than in those without inflammation. In the cases in which disease status was evaluated, 70% of the patients were free of disease or had no evidence of recurrence at autopsy.