JMA Journal

Figure 1. CT showed a slightly high-density mass in the right parieto-occipital region with peritumoral edema (A). The bone window view showed no signs of invasion by the tumor (B).
CT: computed tomography.

Figure 2. MRI. Dural-based extra-axial mass lesion showed slight hyperintensity in diffusion-weighted image (A), isointensity in T1-weighted image (B), and slight hyperintensity in T2-weighted image (C). Post-contrast scans showed homogeneous enhancement of the mass with a long dural tail sign (D).
MRI: magnetic resonance imaging.

Figure 3. The tumor is histologically composed of large lymphoid cells with a predominantly diffuse growth pattern (HE stain) (A). The tumor cells are immunoreactive for CD20 (B).
HE: hematoxylin and eosin.