Figure 1.

Imaging features of primary central nervous system lymphoma. (A) An axial T2-weighted magnetic resonance image shows a large left-sided mass primarily located in the basal ganglia/thalamus with considerable perifocal edema. (B) Diffusion-weighted imaging (apparent diffusion coefficient map) demonstrates diffusion restriction in the periphery of the tumor, indicating high cellularity. (C) Following intravenous contrast medium administration, relatively little inhomogeneous enhancement is seen at the margins of the mass.