Neurological Involvement in Adult‐Onset Secondary Hemophagocytic Lymphohistiocytosis: Clinical Features and Prognostic Implications

CNS involvement defines a severe phenotype of adult-onset sHLH, characterized by malignancy-prone etiology, intense neuroinflammation, and poor prognosis. We establish CNS involvement as an independent predictor of mortality, underscoring the critical need for early recognition and CNS-directed therapies.