amyloid plaque
Pronunciation: AM-ih-loyd plak
Extracellular protein deposits composed primarily of amyloid beta peptide, a pathological hallmark of Alzheimer's disease.
Full Definition
Amyloid plaques are extracellular deposits of misfolded amyloid beta (Aβ) peptide that accumulate in the brain parenchyma and blood vessel walls in Alzheimer's disease and related conditions. These plaques are one of the two major pathological features of Alzheimer's disease, along with neurofibrillary tangles. Plaques can be classified as diffuse (without neuritic component) or neuritic (containing dystrophic neurites and often associated with local inflammatory responses). The distribution and density of amyloid plaques are used for pathological staging and diagnosis according to established criteria such as CERAD and Thal phases.
Usage
Usage note: Specify plaque type (diffuse vs neuritic) and staining method; distinguish from intracellular aggregates.
In Context
- "Congo red staining demonstrated numerous amyloid plaques with apple-green birefringence." — Alzheimer's pathology report
- "Amyloid plaque burden was quantified using stereological methods." — Research methodology description