RecruitingMetabolic and Immunomic Differential Analysis of Primary Central Nervous System Diffuse Large B-Cell LymphomaThis study is a prospective cohort study. The case group will include patients with primary central nervous system lymphoma confirmed by imaging and pathology. The control group will include patients with pathologically confirmed diffuse large B-cell lymphoma who have been excluded from central nervous system involvement, as well as age- and gender-matched healthy volunteers (hematopoietic stem cell donors). Baseline data (as described below) will be collected. Patients with primary CNS lymphoma will undergo follow-up every 3 months, with immediate follow-up if clinical symptoms arise.