Macrophage Activation Syndrome/Secondary Hemophagocytic Lymphohistiocytosis in Adult-Onset Still's Disease: An Uncommon Initial Presentation in a Young Nepalese Female: A Case Report.

Hemophagocytic lymphohistiocytosis (HLH), is a fatal systemic hyperinflammatory syndrome. HLH may be due to immunosuppression, infections, cancer, or autoimmune diseases with fever and cytopenia. HLH which occurs in adult-onset Stills disease (AOSD) is called secondary HLH, also known as macrophage activation syndrome (MAS).