Dercum disease is a very rare condition which can be observed and recognized in daily clinical practice. This is a chronic processing disorder with unknown aetiology. The most characteristic symptom is the appearance of painful multiple nodules with fat deposits observed in subcutaneous soft tissue various body regions. Nodular changes can exert a pressure and are responsible for feeling significant pain. Pathogenesis of the disease is still unknown. Nevertheless, the most important players are proinflammatory cytokines, mainly TNF-α. Widespread pain is especially associated with dynamic changes of the autonomic central nervous system. Postmenopausal obese women are the most frequent targets. Men are affected less frequently - only in 16% of the adult population. We have observed a 49-year-old osteoarthritis woman after the right hip replacement who was admitted to hospital because of persistent low back pain and many painful nodular subcutaneous tumours. Small fat painless deposits occurred at the beginning of the disease. In the next two years, they enlarged and became painful and hyperalgesic with multifocal body distribution. The patient was treated with pain killers and non-steroidal anti-inflammatory drugs without any sufficient clinical effect. Previously, at the dermatology unit, a biopsy was done and Dercum disease was suspected based on multifocal nodular fat deposits recognized as adiposis dolorosa in histopathological studies. Dercum disease was first described in 1892 by Francis Xavier Dercum, an American neurologist from Philadelphia. It has remained a rare disease, which is difficult to diagnose. Differentiation and treatment of this clinical entity may be relevant in the rheumatology practice. The paper discusses a clinical picture of a patient with Dercum disease, pathogenesis and distribution of skin lesions (Table I). Moreover, a close correlation of this disease with rheumatologic daily practice has been determined. Photographic documentation of the most painful nodular skin lesions is also presented (Fig. 1-3).