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case_images: Magnetic resonance imaging findings (a) 14 years earlier and (b) upon admittance.
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case_images: A brain magnetic resonance imaging (MRI) scan with MRI angiography was acquired that revealed frontal bilateral pachymeningitis and left frontal lobe parenchymal inflammatory infiltrate (Figure 1).
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case_images: Histologic findings of the biopsy. (a) Dural biopsy shows heavy lymphoplasmacytic inflammation and fibrosis (hematoxylin-eosin staining, original magnification 200x). (b) Immunohistochemical double staining shows increased number of IgG4 + plasma cells (brown) with abundant IgG + plasma cells (red) (original magnification 400x).
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case_images: The biopsy revealed thickened and fibrotic dura with dense lymphoplasmacytic inflammation (Figure 2).
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case_images: Magnetic resonance imaging findings (a) 3 months and (b) 7 months after initiation of the treatment.
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case_images: After 3 months of rituximab-treatment, the previously observed brain parenchymal changes and pachymeningitis were no longer observable in the brain MRI with gadolinium enhancement nor had new lesions emerged (Figure 3). After 7 months from initiation of rituximab, there were no neurological symptoms or findings, and follow-up brain MRI was normal (Figure 3).