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Why are neuritic plaques and neurofibrillary tangles examined during an Alzheimer disease autopsy?
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Alzheimer disease
Histopathologic image of neuritic plaques in the cerebral cortex in a patient with Alzheimer disease of presenile onset (onset before age 65).
Neuritic plaques and neurofibrillary tangles are examined during an autopsy because their presence in the brain is used to diagnose Alzheimer disease.1
These two features are characteristic tissue lesions found in the cerebral cortex of patients with the disease:2
- Neuritic plaques: Also known as amyloid or senile plaques, these consist of deteriorating neuronal material surrounding a core of a sticky protein called amyloid beta, which is derived from amyloid precursor protein.12
- Neurofibrillary tangles: These are twisted fibers of a protein called tau located within neurons.12
While both structures are thought to interfere with normal cellular functioning, it remains unclear whether they are a primary cause or a consequence of the disease. Although they may appear in smaller amounts in healthy elderly individuals, their presence is a hallmark diagnostic indicator of Alzheimer disease.12