The histopathologic diagnoses in 718 brain tumor patients entered in the Brain Tumor Study Group were reviewed, as well as those for 53 of these patients who were reviewed, as well as those for 53 of these patients who were autopsied later. This review documented instances of progression of histologic analplasia. Of particular interest in the autopsied cases were several instances of extensive necrosis in white matter distant from persisting glioma following chemotherapy and radiotherapy. This observation suggested the presence of a structural and/or metabolic alteration in the diseased hemisphere that perhaps makes it more susceptible to further alterations secondary to the adjunctive therapy.