Introduction. Dermatofibrosarcoma protuberans (DFSP) is a rare sarcoma of the skin and subcutaneous tissue. The most common clinical problem is its local recurrence. The therapeutic procedure of choice is radical surgery. In the case of inoperable disease, targeted therapy with imatinib, a tyrosine kinase inhibitor, may cause significant reduction of tumor volume and even enable radical surgery.

Objective. We present the effectiveness of imatinib for the treatment of unresectable DFSP localized in the area of the shoulder joint of a 62-year-old woman.

Case report. The patient met the criteria for inclusion in treatment with imatinib. After 3 cycles of treatment, partial regression of the lesions (above 50%) was observed. Therapy was complicated by hepatological side effects during the sixth cycle. Treatment was continued with a reduced dose when transaminase levels normalized. In a physical examination and imaging studies, further regression was observed. The patient has regained considerable mobility of the shoulder joint. A decision to continue the treatment has been made.

Conclusions. The use of imatinib allowed a clinical benefit to be gained in the form of significant regression of lesions. A very good treatment response and significant improvement in quality of life of the patient were achieved. The patient has been treated with imatinib for 30 months.