Fatal necrotizing encephalopathy complicating treatment of malignant gliomas with intra-arterial BCNU and irradiation: a pathological study.

We describe the neuropathologic findings at autopsy in six patients who developed a progressive encephalopathy complicating the treatment of malignant gliomas with combined intra-arterial 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and cerebral irradiation. Four brains were free of tumor and one contained a microscopic focus of residual glioma. In only one case was there evidence of tumor progression. A disseminated process characterized by miliary foci of necrosis with mineralizing axonopathy was present in all cases, restricted to the internal carotid distribution of the perfused hemisphere and involving primarily though not exclusively the white matter, which was diffusely and severely edematous. This was combined in 3 cases with a histologically dissimilar, massive necrotizing leukoencephalopathy indistinguishable from pure radionecrosis. Much of the toxicity of this therapy is mediated by vascular injury, but the disseminated necrotizing lesion probably reflects, at least in part, direct neural damage.