PMC6863980_01
Axial T1-weighted (A), T2-weighted (B), and fluid-attenuated inversion recovery (FLAIR) (C) demonstrating a heterogeneous mass centered in the left parietal lobe. T1-weighted gadolinium-enhanced (D) MRI showing an irregular peripheral enhancement mass with a central non-enhancing area. (E-H) Postoperative MRI scan showing a flaky edema area in the left frontotemporal lobe. Axial T1-weighted (I), T2-weighted (J), fluid-attenuated inversion recovery (FLAIR) (K), and T1-weighted gadolinium-enhanced (L) MRI showing no evidence of contrast enhancement in the left parietal lobe on 6 month follow-up.
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F1
MRI showed a solitary 2.8 cm x 2.6 cm x 4.1 cm irregular peripheral enhancement mass with a central non-enhancing area centered in the left parietal lobe (Figures 1A-D). Magnetic resonance angiography displayed mildly abnormal with no sign of vasculitis; slight narrowing was observed in the bilateral siphon carotid arteries, bilateral anterior cerebral arteries, and the M1 segment of the left middle cerebral artery. After surgery, the patient's consciousness deteriorated, and a postoperative MRI scan demonstrated flaky extensive perifocal edema that could not be explained by glioma (Figures 1E-H). A repeat brain MRI after 6 months of treatment showed that the lesion had nearly disappeared with the resolution of edema and mass effect (Figures 1I-L).
Hematoxylin and eosin staining magnified 40x (A) and 200x (B) showing dense perivascular lymphohistiocytic infiltration.
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However, the histopathological examinations revealed a lymphocytic inflammatory infiltrate in the vessel walls and perivascular zones, and parts of the vessels demonstrated necrotic wall damage and contained hyaline microthrombi, consistent with central nervous system vasculitis (Figure 2).