A relatively well defined region of hypodensity within the left side of the splenium of the corpus callosum extends laterally along the left forceps major. Further less defined hypodensity extends anteriorly along the inferior left temporal lobe as well as possibly within the periventricular white matter. Post-contrast images do not demonstrate any suspicious enhancement in these regions, or elsewhere in the brain.
No intracranial hemorrhage. Ventricles and sulci are within normal limits for the patient's stated age.
There is bright FLAIR/T2 signal involving the left mesial temporal lobe extending posteriorly to involve the left occipital lobe and splenium of the corpus callosum. Small areas of liquefaction are seen within the left splenium and hippocampal body. 2.0 cm area of bright T2/FLAIR signal is also seen adjacent to the anterior body of the right lateral ventricle.
There are patchy leptomeningeal- and gyral-pattern of enhancement seen involving the left parahippocampal gyrus extending into the occipital lobe. Perivenular leptomeningeal enhancement and bright FLAIR/T2 signal are seen in periventricular deep white matter bilaterally. Scattered nodular enhancement are also seen along the right lateral ventricle, centrum semiovale, caudate head and thalamus. There is also tentorial dural thickening and enhancement.
No definite area of diffusion restriction seen, with bright DWI signal due to T2* shine through.
MRS over the right periventricular bright signal demonstrate increased Cho and reduced NAA even after allowing for baseline shift. This however is nonspecific. MRA is unremarkable (not shown).
No convincing abnormality is identified. Specifically no definite stenosis / dilatation / beading.
This patient went on to have a dural and cerebral biopsy.
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 tumor 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 tumor 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.
Case Discussion
The diagnosis of primary cerebral angiitis is difficult to make without a biopsy, and even histology can be challenging. An accurate diagnosis is however essential as treatment is protracted and has significant side effects.
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