Imaging of Lymphomas Involving the CNS: An Update-Review of the Full Spectrum of Disease with an Emphasis on the World Health Organization Classifications of CNS Tumors 2021 and Hematolymphoid Tumors 2022

A–C: Primary DLBCLs of the CNS, EBV-negative, with imaging signs of central necrosis (A) and tumoral hemorrhage (B and C). D–G: DSC-PWI features of a left frontal primary DLBCL of the CNS, EBV-negative (D). Low-to-intermediate CBV on noncorrected (E) and corrected (F) color maps. Characteristic lymphoma DSC-PWI time-intensity curve morphology with ascending-part of the curve recovering signal intensity far above the baseline (high PSR) (G).

Sentinel inflammatory lesions preceding primary DLBCL of the CNS. Two enhancing periventricular temporal lesions were detected in a patient (A). A biopsy was obtained, and histopathology showed an inflammatory infiltrate without evidence of neoplasia. The lesions disappeared on further imaging controls during the following 2 years (B). In a subsequent MR imaging control, new masslike lesions reappeared (C and D). A biopsy of the new lesions yielded the final histopathologic diagnosis of primary DLBCL of the CNS.

Primary DLBCLs of the CNS, EBV-positive (immunodeficiency/dysregulation-associated). Single (A) and multiple (B) lesions with prominent necrosis (C and E) and tumoral hemorrhage (D and F). Heterogeneous deep T2 hypointensity (H) of the nonenhancing central content (G) of lesions, so-called necrosis. Low-intermediate CBV on the corrected color map (I) and DSC-PWI time-intensity curve with high PSR (J), also very characteristic of this lymphoma subtype.

Intravascular lymphoma (A–D). Acute patched ischemia-like lesions on DWI (A), hemorrhages (B), and an area of enhancement (C), which grows on the subsequent few days of imaging control (D). Dashed arrow in C–D indicates the growth of the same enhancing-lesion in few days. DLBCL following a lymphomatosis cerebri pattern (E–J): extensive, patched, bilateral, and diffuse FLAIR hyperintensity on the basal ganglia (E) and white matter (F), with an area of enhancement in the left cerebellum (H) and associated leptomeningeal disease (arrow in H). Intermediate CBV in DSC-PWI color maps (I) and characteristic high PSR and time-intensity curve morphology (J). Tumoral pattern on ¹H-MR spectroscopy at long TE with a high Cho-to-NAA ratio (H) and absent mIns at the short TE (not shown), helpful in the differential diagnosis with nontumoral entities and gliomatosis cerebri, respectively.

Dural lymphomas. MALT dural lymphoma (A–D) with extra-axial lesion features such as a CSF cleft (A) and a wide-implantation dural base with soft marginal angles (C), as well as T2-hypointensity (A) and diffusion restriction (B). Almost normal calvarial bone; only subtle sclerosis seen (D), despite the great soft-tissue component on both sides of the diploe (A–C). Similar imaging features with minimal bone destruction and a subtle permeative pattern (F) in comparison with the prominent soft-tissue component (E) in another diffuse large B-cell dural lymphoma (E and F).

NK/T-cell lymphoma presenting with a lymphomatosis cerebri radiologic pattern (A–C). Patched and diffuse, bilateral and asymmetric, deep and subcortical, hyperintense lesions on FLAIR (A and B) without contrast enhancement (C).