23. Senile plaques and neurofibrillar degeneration

Page created on March 20, 2019. Not updated since.

Staining: Silver stain (Bielschowsky)

Organ: Brain, hippocampus


The hippocampus is visible and that’s where the characteristic findings are visible on this slide.

Senile plaques are extracellular deposits of β-amyloid that are surrounded by silver-positive proteins. The amyloids themselves aren’t stained by silver and are therefore pale. These plaques are therefore visible as large black foci with a pale core.

Neurofibrillary tangles are intracellular bundles of hyperphosphorylated tau. These tangles are stained by silver and causes the neurons to be stained black.

Diagnosis: Alzheimer disease (senile plaques, neurofibrillary tangles)

Risk factors:

  • Genetic factors
  • Down syndrome
  • Lack of physical activity
  • Traumatic brain injury
  • Old age


Alzheimer’s disease most commonly affects the hippocampus first, and then the frontal and temporal lobes before it becomes a diffuse process.

This slide is overstained, so the characteristic findings are therefore hard to distinguish from background noise.

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One thought on “23. Senile plaques and neurofibrillar degeneration”

  1. There should also be amyloid angiopathy found in the walls of the leptomeningeal and cerebral vessels, this should expand the walls of the vessels. I dont think its stained with silver but it is congophilic.

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