Evolution of prognostic systems in LCH. (Left) Traditional risk-organ–based prognostication categorizes patients based on the presence or absence of risk-organ involvement, affecting overall survival. Patients with risk-organ involvement exhibit poorer survival compared with those without. (Right) Molecular-based prognostication highlights the role of PBMC-BRAF^V600E mutation status incorporated in the LangIndex in predicting event-free survival and the development of LCH-ND. The evolution of LCH over time is illustrated as a transition from a high-mortality disease to a chronic, incurable condition with associated morbidity. Professional illustration by Somersault18:24.