Cytological demonstration of features of Alzheimer's disease using brain smear technique

The major diagnostic histopathological features of moderate to severe Alzheimer's disease (AD) are amyloid rich neurofibrillary tangles (NFTs) and neuritic plaques (NPs) containing beta A4 peptide. As the frequency of stereotactic brain biopsies is increasing, the diagnostic cytological features of AD are of relevance. Our study presents the brain smear features of five autopsied patients with moderate to severe AD both clinically and pathologically. NFTs and NPs were identified in 100% of smears. Amyloid neuropil threads (NTs), a more recently identified hallmark of AD, were also seen in all smears. Segmental beta A4 peptide deposition within vessels, clustering of plaques around capillaries, and NTs were more obvious by the smear technique than in histological sections.