Multiple system atrophy (MSA) with massive macrophage infiltration in the ponto-cerebellar afferent system.

Multiple system atrophy (MSA) is characterized pathologically by a systemic degeneration of the olivopontocerebellar (OPC), striatonigral (SN) and autonomic systems. Massive glial cytoplasmic inclusions (GCIs) are specific for this disease. Massive lipid-laden macrophage infiltration in the degenerating tracts has not been described up to now. We here report a case of MSA with this rare event in the ponto-cerebellar (cerebellopetal) fibers. The patient, 54-year-old housewife, developed ataxia. At the age of 55 years, she was diagnosed as having MSA by cerebellar ataxia, extrapyramidal signs, autonomic failure and Horner syndrome. She died from asphyxia at the age of 57. The autopsy revealed OPC and SN system atrophy, degeneration and numerous GCIs, compatible with MSA. Numerous lipid-laden macrophages were seen in the pontine nuclei and its transverse fibers including the white matter of the cerebellum, which has not been reported up to now. There was no macrophage infiltration in the other areas. Transient ischemia, infarction and wallerian degeneration do not account for this rare event. The ponto-cerebellar (cerebellopetal) tract pathology, as observed by postmortem neuropathological study, may occur in the context of MSA.