Intermittent meningitic reaction with severe basophilia and eosinophilia in CNS leukaemia.

Light- and electron-microscope studies were performed on CSF cells from a patient with CNS leukaemia presenting with an intermittent meningitic reaction. Numerous fully matured basophilic and eosinophilic granulocytes with excess glycogen content accompained undifferentiated leukaemic blast cells in the CSF. Such a CSF cell reaction has not been previously reported. It is suggested that this isolated CSF reaction represents a special type of immediate hypersensitivity reaction triggered by an abnormal leukaemic giant cell clone, and mitigated by the accompanying eosinophilic granulocytes.