Atypical Imaging Features of Epstein-Barr Virus–Positive Primary Central Nervous System Lymphomas in Patients without AIDS

Abstract

Recent clinical experience with EBV-positive PCNSL in patients without acquired immune deficiency syndrome showed that they tended to have atypical features seen on conventional MR imaging. The purpose of our study was to evaluate the MR imaging features of EBV-positive PCNSL in patients without AIDS and to compare these imaging findings with those of EBV-negative PCNSL. MR images were obtained in 55 consecutive patients with pathologically proved EBV-positive (n = 10) or EBV-negative (n = 45) PCNSL. We statistically analyzed the differences between the patient groups regarding the occurrence of tumor necrosis or hemorrhage and ADC, rCBVmax, rCBVr, and the Cho/NAA ratio in the tumor area. Tumor necrosis and hemorrhage were observed in 9 (90%) and 7 (70%), respectively, of the patients with EBV-positive PCNSL; necrosis was observed in 8 (18%), and hemorrhage, in 3 (7%) patients with EBV-negative PCNSL (P < .0001 each). The necrotic core was hyperintense relative to contralateral white matter, as seen on DWI in 4 patients with EBV-positive PCNSL, though the ADC between the 2 patient groups did not differ significantly. rCBVmax, rCBVr, and the Cho/NAA ratios did not differ significantly between the 2 groups. The sensitivity and specificity of necrosis and hemorrhage for differentiating the 2 groups were 89.2% and 81.7% and 78.5% and 94.1%, respectively. Our initial clinical experience with a small number of patients suggests that EBV-positive PCNSL in patients without AIDS tends to present with atypical MR imaging features.