[Fever masks of malignant tumors]

During 5 years, the authors followed up 129 patients referred to the clinic with a diagnosis of fever of unclear genesis. In 36.4% of cases, fever masked malignant neoplasms. Hyperthermia was ahead of the emergence of the symptoms of a tumor (maximally up to 12 years), dominated or was the only symptom for a time being. However, in most cases it combined with other paraneoplastic masks (rheumatic, hematological, hepatological, etc), was resistant to the treatment and disappeared after radical treatment.