By histologic type, the 5-year cumulative incidence of CNS relapse was 1.8% (95%CI: 0.5–4.9%) in PTCL-NOS, 0.7% (95%CI: 0.1–3.6%) in AITL, 5.4% (95%CI: 1.8–12.3%) in ALK+ ALCL, 2.1% (95%CI: 0.4–6.6%) in ALK-ALCL and 3.7% (95%CI: 0.1–11.3%) in ENKL (Fig 1B). Here, ALK is linked to anaplastic large cell lymphoma.