[A case of atypical progressive supranuclear palsy with degeneration of the fronto-pontine tracts, and without grumose degeneration of the dentate nucleus].

An autopsy case of progressive supranuclear palsy (PSP) with degeneration of the fronto-pontine tracts of the midbrain and pons, and without grumose degeneration of the dentate nucleus is reported. A 72-year-old woman was suffering from dysarthria and gait disturbance. Moderate dementia was noted and gradually worsened. Pyramidal and extrapyramidal signs and cerebellar ataxia were not observed. Eye movements were fully preserved. Brain CT showed cerebellar atrophy. Three years later, she was unable to stand or move, and became mutistic. At the age of 75, she died suddenly. The duration of her illness was approximately 4 years. Clinical diagnosis was LCCA (late cortical cerebellar atrophy). Neuropathological examination revealed gliosis of the deep layers of the cerebral cortex around the precentral gyrus, fronto-pontine tracts degeneration (posterior part of the anterior crus, genu and anterior part of the posterior crus of the internal capsule, cerebral peduncles of the midbrain, pontine base and pyramis of the medulla oblongata). Also, atrophy of the pons and marked degeneration of the superior colliculi and substantia nigra were observed. Neurofibrillary tangles (NFTs) and glial fibrillary tangles (GFTs) were found in the subcortical nuclei. These findings were almost consistent with PSP. However, the following differed from those of previously reported typical PSP cases: firstly, mild gliosis in the reticular formation of the midbrain; secondly, few NFTs in the pontine nuclei and superior colliculi and; thirdly, no grumose degeneration in the dentate nucleus. In addition, clinical symptoms of the present case are not consistent with PSP. Therefore, we concluded this case to be an atypical PSP both clinically and neuropathologically.