Dermatofibrosarcoma protuberans (DFSP) is a mesenchymal neoplasm of fibrohistiocytic origin of moderate malignancy. The pathogenesis of DFSP involves chromosomal translocation, which leads to the formation of a fusion protein that promotes tumor growth due to increased production of platelet growth factor (PDGF). Clinically, it begins with an asymptomatic fibrous papule or firm plaques, which gradually over the course of several years become enlarged with the formation of asymmetrical multi-nodular structure of purple or red-brown color. The standards of diagnosis is a histological examination with the detection of a poor limited infiltrate indermis of a storiform architecture consisting of monomorphic spindle cells and diffuse CD34+ staining during immunohistochemistry. Complete surgical excision is considered the gold standard of treatment. Clinical case: female patient, 35 years old with a lesion in the form of a dense plaque in right subclavian area was examined by a dermatologist. The primary diagnosis was made as "morphea". In a year a slight growth of the lesion and the appearance of small firm nodules asymmetrically along the periphery were noted. According to the results of histological and immunohistochemistry studies the diagnosis of DFSP was made, the patient was referred to an oncologist for complete tumor removal.