Abstract
Borderline phyllodes tumor is a rare and benign form of breast cancer with malignant potential. According to the World Health Organization (WHO), phyllodes tumor is classified into three categories: benign, borderline, and malignant. The treatment of phyllodes tumor is wide focal excision combined with radiotherapy and chemotherapy in certain cases. Herein, we report a 47-year-old female who presented with a giant borderline mass approximately 19.5 x 16.9 x 9.3 cm in size. From medical history, we noticed that the mass begun to develop during puberty. Wide focal excision of the tumor and immediate implant-based reconstruction with free nipple graft was performed, with the tumor specimen measuring 16.5 x 14.2 x 8.7 cm. Histological examination reported a borderline phyllodes tumor, and in this case, the patient did not undergo adjuvant treatment.