Subacute Multifocal Leukoencephalopathy

THE OCCURRENCE of unique demyelinative lesions of the brain associated with malignant diseases of the reticuloendothelial system was first described by Astrom et al.1This disorder, to which the name progressive multifocal leukoencephalopathy has been applied, is most often associated with leukemia and lymphoma. It has been reported in a variety of other disorders including tuberculosis,2sarcoidosis,3carcinomatosis,4multiple myeloma,5,6Whipple's disease,7primary hypersplenism,8polycythemia vera,9and coronary artery disease.10The medical literature contains about 60 pathologically verified cases of progressive multifocal leukoencephalopathy. Included within this group is a case described by Castaigne et al,11the neuropathological features of which did not conform to those usually observed in progressive multifocal leukoencephalopathy. The case which follows, observed in association with reticulum cell sarcoma, is being presented because of its unusual pathological features which, like those of the French case,11