Pediatric MYD88-wildtype PCNS-LBCL is associated with favorable clinical outcomes compared with its adult-type counterpart. (A-F) Representative radiologic and histopathologic findings in pediatric- and adult-type PCNS-LBCL. Preoperative T1-weighted postcontrast magnetic resonance images of patients with pediatric type, MYD88-wildtype (A) or adult type, MYD88-mutant (D) PCNS-LBCL, showing overlapping radiologic features, including intraparenchymal mass lesions with diffuse enhancement and significant edema in the adjacent white matter. Histologic analysis showed sheets of malignant large B-cells diffusely expressing CD20. Hematoxylin and eosin, magnification ×400 (B,E); and CD20, original magnification, ×400 (C,F). (G) Kaplan-Meier survival plot of 7 patients with pediatric type, MYD88-wildtype PCNS-LBCL. (H) Kaplan-Meier meta-analysis of 53 pediatric and young-adult patients with PCNS-LBCL stratified by age ≤ 25 years vs 26 to 40 years.