Background: A case of Still's disease in the adult, an uncommon seronegative rheumatoid arthritis-like disease with prominent systemic features is reported. This case did not show the typical clinical features and appeared like a fever of unknown origin.
Case report: A 60 year-old female was admitted to the hospital for high fever occurred two months before without other important clinical symptoms and signs. Laboratory tests and morphologic images were negative for infectious diseases, tumours and immunological disorders. The course of the disease worsened and an hepatic failure threatened the patient life. The onset of many other typical clinical features, i.e. joints pain, characteristic skin rash, splenomegaly, throat pain, serositis and weight loss, led us to make a sure diagnosis and to save the patient with steroid therapy.