Argyrophilic grains in late-onset Creutzfeldt-Jakob diseased brain.

Braak's argyrophilic grains (ArG) are spindle-shaped structures originally described in patients with dementia. Herein, a unique case of sporadic Creutzfeldt-Jakob disease (CJD) accompanied by numerous ArG is presented. The pathological picture was typical of CJD based on the findings of routine hematoxylin-eosin staining. The highest density of ArG was observed throughout the parahippocampal gyrus and the temporal gyri; however, the sector CA1 of the hippocampus showed less ArG. An immunohistochemical analysis for prion protein (PrP) revealed diffuse fine neuropil staining in the cerebral cortex, while the ArG themselves did not demonstrate any immunoreaction for PrP. No correlation was observed between the densities of ArG and either the presence of senile plaques, neurofibrillary tangles or neuropil threads in the present case. To our knowledge, this is the first report of CJD demonstrating numerous ArG.