Subacute necrotizing encephalomyelopathy of infancy and childhood.

Subacute necrotizing encephalomyelopathy appears to be a distinct pathological entity occurring in infancy and childhood. The neurological manifestations are diverse but the course is one of progressive deterioration. The aetiology is not known and no treatment is available. Histologically the lesion is characterized by multiple areas of necrosis and is remarkable because of a lack of glial or small cell reaction. There is a predilection for the brain-stem but the entire neuraxis may be involved. The mammillary bodies are generally spared. Capillary proliferation and status spongiosus are seen either separately or more commonly in combination. Areas may be found in which no neural tissue is spared or a nucleus may selectively be involved with sparing of adjacent white matter, or occasionally only white matter is involved. In this account the twenty-first, twenty-second and twenty-third cases, one of which had a lesion in the mammillary body, are reported. Possible aetiological mechanisms are discussed.