Case 113. 
Gerstmann-Straussler-Scheinker (GSS) disease (54 y-o F)
Familial progressive dementia with spastic paralysis (clinical course 23 years)
Key words : GSS disease, prion, β-amyloid protein, Kuru spot
Numerous senile plaques (amyloid plaques) are formed in the cerebral cortex, as well as in the cerbellar cortex and spinal cord. Neurofibrillary tangles are formed in some neurons in this case (HE). The brain weighed 800 g.   The neurofibrillary tangle is immunoreactive for tau protein revealed by immunostaining. This is a special subtype of GSS disease with neurofibrillary changes.
Two types of amyloid plaques are recognized in GSS disease: Monocentric "Kuru plaques" vs. multicentric (satellite-forming) "GSS plaques". The latter is strongly PAS-positive, while the former is weakly PAS-reactive.   Beta-amyloid protein immunoreactivity is observed in the satellite-forming GSS plaques and also in the vascular wall (immunostaining).