Adult-onset Still's disease as a mask of Hodgkin lymphoma.

Adult-onset Still's disease is a rare disorder, which creates difficulties in making a proper diagnosis. Ambiguous symptoms and results of auxiliary tests, lack of unequivocal diagnostic tests and the need to exclude other causes of the disease are major problems in clinical practice. A case of a 22-year-old woman with dominated recurrent fever, significantly elevated inflammation markers and arthritis is presented. Based on clinical signs after exclusion of infection, hematological and other reasons, the patient was diagnosed with adult-onset Still's disease. Standard treatment, with high doses of glucocorticoids and a disease-modifying drug, was applied, without the anticipated effects. The diagnostic tests were conducted again due to the lack of clinical improvement, increase of inflammatory markers and unusual response to treatment. A new symptom of significance, i.e. mediastinal lymphadenopathy, was found. After the histopathological examination of lymph nodes, Hodgkin's disease was diagnosed and targeted therapy for hematological malignancy was applied.