The sections contain cerebral cortex and white matter. A few of the leptomeningeal and cortical blood vessels contain amorphous eosinophilic material within the walls (Fig 1 - A&B). There is no evidence of thrombosis or vasculitis. No haemorrhage or infarcts are noted.
The Congo red stain (Fig 1 - C) is positive in the blood vessels for amyloid. It shows apple-green birefringence under polarised light (Fig 1 - D).
The B-amyloid immunostain (Fig 2 - A&B) is also positive in the vessels. It highlights several amyloid plaques in the cortex. These are not significantly increased in numbers. Assessment for dementia/Alzheimer's disease would require more dedicated biopsy samples.
No evidence of granulomatous angiitis to suggest CAA related inflammation. (Fig 2 - C) is from a different patient, highlighting the appearances of granulomatous angiitis.
Right frontal cortex biopsy: Amyloid angiopathy.