Demyelination with hemophagocytic lymphohistiocytosis of the CNS.

A case of hemophagocytic lymphohistiocytosis with central nervous system involvement in an infant is presented. Marked demyelination of cerebral and cerebellar white matter is associated with an intense histiocytic infiltrations and astrogliosis. Histiocytes phagocytic of erythrocytes and lymphocytes are noted in a meningeal, subependymal, and perivascular distribution. Severe depletion of lymphoid tissue, associated with histiocytic infiltration, is also seen in multiple organs. While the etiology of this disease is unknown, alterations in the immune response and possible viral relationships are explored.