Encephalomyelitis and demyelinating diseases in patients with extracerebral malignant tumors

We examined central nervous system (CNS) lesions in 456 patients with primary extracerebral malignant tumors. Inflammatory reactions caused by viral (progressive multifocal leukoencephalopathy (PML), herpes zoster varicella), fungal, or bacterial infections could be demonstrated in 20 patients. In a further 19 patients, the brain tissue showed lymphocyte infiltrates of unknown etiology and, in four of these, autopsy revealed probable paraneoplastic, non-bacterial, endocarditis as a possible explanation for the local inflammatory reaction. The frequency of thrombophlebitis, non-arteriosclerotic thrombosis and arteritis was significantly higher than in a control group of 2052 tumor-free patients. Focal spongiform-axonopathic lesions (24 cases) as well as diffuse leukoencephalopathy (11 cases) were interpreted as probably being at least in part paraneoplastic because the same alterations could also be observed in patients who had never undergone cytostatic or radiation therapy. The possible pathogenetic conditions are discussed and a classification of these tumor-accompanying, but not always tumor-dependent, lesions suggested.