Disseminated necrotizing encephalopathy induced by methotrexate therapy alone.

This report describes the autopsy findings in a 62-year-old woman who died of pneumonia and disseminated necrotizing encephalopathy following intrathecal methotrexate (MTX) therapy for meningeal infiltration of lymphoma cells. Radiation therapy was not given. An interesting pathological finding was exudation of fibrin around the small vessels in the demyelinated foci, suggesting increased vascular permeability. This observation and analysis of previous reports of similar cases suggest that primary vascular injury, probably due to the direct effect of MTX, may be involved in the pathogenesis of MTX-related disseminated necrotizing encephalopathy.