[Radiation-Associated Angiosarcoma of the Breast-A Case Report].

Radiation-induced angiosarcoma(RIAS)of the breast is a rare malignant tumor occurring after breast-conserving therapy. A 70-year-old woman underwent breast-conserving surgery followed by radiation therapy for right breast cancer at the age of 66. Four years and 10 months after surgery, she noticed a mass with skin redness in her right breast. A biopsy revealed angiosarcoma, and she was subsequently referred to our hospital. Physical examination demonstrated a 55 mm ulcerated mass. Ultrasound, CT, and MRI examinations showed a poorly demarcated tumor invading the skin without evidence of distant metastasis. Wide surgical resection, including affected skin, was performed along with reconstruction using a latissimus dorsi flap. Histopathological examination confirmed a 65 mm angiosarcoma with negative surgical margins. Postoperatively, delayed wound healing occurred, necessitating hyperbaric oxygen therapy. The patient was discharged 35 days after surgery; no recurrence was observed at the 6-month follow-up. Early diagnosis, extensive surgical resection, and coordinated multidisciplinary care involving reconstructive procedures are essential for achieving favorable clinical outcomes in patients with RIAS.