abspara0015">We present the case of a 44-year-old immunocompetent woman who developed several cerebral and cerebellar lesions on magnetic resonance imaging (MRI). A partial resection of the cerebellar contrast-enhancing lesion showed active inflammation with large destructive process but no evidence of B-cell lymphoma. Her disease was in a relapsing-remitting course for 28 months and progressed with new MRI findings of more contrast-enhancing lesions. She died at 33 months after the initial presentation. Postmortem examination revealed B-cell PCNSL with extensive involvement but sparing a few brain regions, including the previous resection site, with only an inflammatory destructive process.
abspara0020">PCNSL may be preceded and accompanied by an inflammatory process that is pathologically distinct from PCNSL. Our case study, in combination with a review of previously published similar cases, supports the hypothesis that the “sentinel” inflammatory lesions may be the first immune response against PCNSL.