Presentation
Transient episodes of expressive aphasia and right-sided numbness
Patient Data
Multiple ill-defined areas of high T2 signal involving mainly the posterior frontal and parietal white matter on the left extending to involve the left caudate, external capsule, thalamus, and periventricular white matter. There is prominent left periventricular and striatocapsular enhancement with involvement of the left and to a lesser extent right thalamus. Additonal punctate regions are scattered elsewhere throughout the brain including adjacent to the midbrain and aqueduct.
Many of these areas also demonstrate signal loss and blooming on susceptibility-weighted images that align with veins that drain into the caudothalamic vein; there may be hemorrhage and/or venous thrombosis. Faint left periventricular frontoparietal area of restricted diffusion.
Conclusion:
Unusual pattern of enhancement with probable venous thrombosis. This has a wide differential diagnosis including vasculitis, intravascular lymphoma and post viral acute necrotizing encephalopathy. Given the patient's demographics demyelinating disease should also be included. Autoimmune glial fibrillary acid protein astrocytopathy is perivascular but usually does not involve the vessel wall. Metastases and diffuse gliomas are felt less likely given the enhancement pattern.
Status post left parietal burr hole for brain biopsy.
Trace amount of expected postsurgical pneumocephalus.
New hemorrhagic material in the left lateral ventricle extending caudally to the third and fourth ventricles.
Extensive ill-defined lesions described on MRI are not well appreciated on CT.
Permanent sections from the 10 o'clock specimens show acute eosinophilic vasculitis. There is focal necrosis of the vascular walls and there is an abundance of eosinophilis in the transmural inflammatory infiltrate.
Permanent sections confirm the intraoperative assessments.
Sections from the 9 o'clock biopsies show mild reactive changes, consistent with mild brain parenchymal reactive changes.
The findings are those of an acute vasculitis with abundant eosinophils i.e. acute eosinophilic granulomatosis. The morphology is consistent with Churg-Strauss.
Case Discussion
As per electronic medical records, previously healthy our patient was referred to specialized neurology services from an outside institution for assessment of a tumefactive brain lesion. She reported 4 episodes of speech disturbances lasting seconds, happened few months apart, and right sided numbness lasting for around 20 minutes. No history of neurological disorder. No constitutional symptoms. Her physical exam was noncontributory.
Though her symptoms were not recurrent, follow-up images demonstrated persistent fronto-parietal left hemispheric ill-defined lesions with additional lesions in the right occipital lobe, left caudate, external capsule, thalamus, and periventricular white matter of the temporal horn. A whole body PET/CT scan was performed (not shown) which excluded a lymphoproliferative disorder such as lymphoma or other systemic process: no distinct dominant FDG foci compared to normal brain parenchyma nor evidence of systemic lymphadenopathy to suggest aggressive lymphoma.
She underwent a stereotactic needle biopsy for tissue analysis.
Her histopathology exam revealed findings consistent with an acute leukocytoclastic CNS vasculitis with abundant eosinophils.
Findings of a vasculitis were also supported by an abnormal CSF analysis consistent of elevated CSF proteins (0.54 for a normal range of 0.15-0.45), increased IgG synthesis (IgG index 1.28 for a normal range of 0.34-0.66; IgG synthesis rate of 27.4 for normal value of < 4.0), and normal CSF glucose 3.2 (normal range 2.5-4.4).
MRV and MRA (not shown) showed no acute abnormality. Our patient did not undergo a cerebral angiogram prior to her biopsy.
Acknowledgments to Dr. Lam, S. for the radiological images and to Dr. Karamchandani, J. for contributing with the microscopic images.
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