PATHOLOGY REVIEW Neuropathology

SUMMARY: Histologically identified intracellular and extracellular inclusions and structures often pro-vide a tissue diagnosis of a specific disease process. Moreover, these deposits may provide clues about the pathogenesis of the disease in which they are found. Two distinctive structures seen within the brains of patients clinically diagnosed with dementia of the Alzheimer type are extracellular plaques and intracellular neurofibrillary tangles. The purpose of this report is to review the significance of plaques and neurofibrillary tangles in the context of Alzheimer disease. Histologically identified cellular deposits often provide atissue diagnosis as well as clues about the pathogenesis of the disease that they represent. Two distinctive structures seen within brains of patients with dementia of the Alzheimer type (DAT) are plaques and tangles. Appreciation of these tissue inclusions enhances the interactions of the neuroradiologist with the neuropathologist, neurologist, geriatric psychiatrist, and geriatrician and deepens the understanding of Alzheimer disease (AD), the all-too-common neurodegenerative disor-der. Moreover, neuroradiologists are likely to play important roles in the future regarding the detection and differential di-agnosis of AD, given the increasing prevalence of DAT in the aging population and promising research aided by such tools as positron-emission tomography (PET), quantitative struc-tural imaging, molecular imaging, diffusion tensor imaging, and functional MR imaging. The purpose of this report is to review the significance of plaques and tangles in AD. Backgroun