The sections show grey and white matter. The leptomeningeal and cortical blood vessels are abnormal. They contain lymphocytes within and outside the vessel walls. No thrombosis or fibrinoid necrosis is identified. The lymphocytes appear small and mature and they do not show any nuclear atypia. In some of the vessels, there are reactive plump endothelial cells. Occasional histiocytes are noted but there are no discrete granulomas or giant cells. No amorphous amyloid deposit is present in the vessel walls on the H&E sections. The parenchyma shows no increased inflammation. No spongioform change is seen in the background and there is no evidence to suggest Creutzfeldt-Jakob disease. No tumour is identified.
The perivascular lymphoid cells are mainly CD3 positive (T-cell marker), along with some CD68 positive histiocytes (not shown). CD20 positive B-cells are sparse (not shown).
Scattered amyloid plaques with positive BA4 amyloid immunostain are identified, being 8-10 plaques per high power field. There is no amyloid angiopathy.
Sections of the dura (not shown) demonstrates no increased inflammation. No granulomas or giant cells are identified. No tumour is seen.
FINAL DIAGNOSIS:
- Brain biopsy:
- Inflammatory changes in the leptomeningeal and cortical blood vessels, consistent with cerebral angiitis.
- Borderline changes of Alzheimer's disease.
- Dura: No significant abnormality seen.