Abstract
The paper aims to introduce the case of an extensive breast malignancy – phyllodes tumor. This type of breast neoplasm is relatively rare. Indeed, it accounts for only 0.3-1% of all breast malignant tumours. In the paper, patient, disease, and treatment methods were described and evaluated. The efficacy of surgical treatment and adjuvant therapy (radiotherapy and chemotherapy) was assessed based on literature data. The authors concluded that late diagnosis of phyllodes tumor causes the necessity of mastectomy and radiotherapy and aggravates the prognosis.