A case of sporadic Creutzfeldt-Jakob disease with both plaque and synaptic-type deposition of prion protein

We report a Japanese case of sporadic Creutzfeldt-Jakob disease (CJD) with particular clinical course and neuropathological findings. A 74-year-old female exhibited parkinsonism and later, dementia, myoclonus as well as visual hallucinations, lacking periodic synchronous discharges in the electroencephalogram. The duration of her illness was 2 years, longer than typical CJD cases which average 8 months’ duration. Gray matter was severely affected, the Ammon’s horn and subicular cortex were well preserved and many kuru plaques were observed in the cerebellum using routine histological stainings. Immunohistochemistry for prion protein (PrP) using both formic acid and hydrolytic autoclaving pretreatment revealed numerous prion plaques throughout the brain together with intense synaptic-type deposition of PrPCJD (abnormal isoform of PrP) in all gray matter examined, particularly in the Ammon’s horn and subicular cortex. The definite combination of these two types of stain has never been reported previously in Japan other than in Gerstmann-Straussler– Scheinker syndrome. Relative resistance of the Ammon’s horn and subicular cortex to the PrPCJD deposition is also discussed.