Brain damage after intrathecal methotrexate.

Ten brains from leukaemic patients given intrathecal methotrexate and 10 from leukaemic patients without intrathecal therapy have been examined. Three of the methodtrexate treated patients appear to have died from their therapy. The histological changes consisted of destruction of oligodendrocytes, sometimes complete over large areas, and sometimes relatively slight. All the patients who survived long enough after treatment showed severe astrocytosis.