AIDS-related primary central nervous system lymphoma

MRI of multifocal AIDS-related primary central nervous system lymphoma in a 54-year-old male presenting with headaches and left-sided weakness. The CD4 count on presentation was 1 cell/microL and the HIV viral load was 856,000 copies/mL. Toxoplasmosis serology was negative. A stereotactic brain biopsy of the right frontal lesion revealed DLBCL with positive staining for EBV.

(A) T2-weighted coronal image demonstrates mixed-intensity mass lesions in the right frontal lobe (thick arrow) and right basal ganglia (arrow). There is moderate T2-hyperintense signal abnormality surrounding each lesion, consistent with edema.

(B) Postcontrast T1-weighted image demonstrates heterogeneous rim enhancement associated with both lesions. Lack of contrast enhancement in the center of the lesions is consistent with central necrosis.

(C) DWI in the axial plane shows increased DWI signal associated with the right frontal lesion (dashed arrow).

(D) ADC shows intermediate ADC signal in the central portion of the right frontal lesion and decreased ADC signal along the right rim (arrowheads). Together with the DWI signal, these ADC values are consistent with restricted diffusion primarily along the rim of the lesion.