Adult onset Still's Disease.

Adult onset Still's disease is a rare systemic condition at the crossroads between auto-inflammatory syndromes and autoimmune diseases, with considerable heterogeneity in terms of clinical presentation, evolution and severity. This article reviews the main advances and lesser known aspects of this entity related to its clinical spectrum (atypical cutaneous lesions, unusual manifestations, macrophage activation syndrome, disease phenotypes), the emerging controversy around its association with delayed malignancy, the search for new biomarkers for its diagnosis, evaluation of prognosis (clinical factors, prognostic indexes and biomarkers to identify patients at risk of severe organ failure or life-threatening complications), and the determinants in the choice of biological treatment.