Abstract
A 38-year-old woman noticed a smooth and movable 8-cm mass in her left breast. She underwent lumpectomy with a diagnosis of a phyllodes tumor. The histological diagnosis was benign, and the surgical margins were negative. One year later, a local recurrence was noticed but she did not consult a medical institute. The tumor increased in size to 23 cm, 1 year and 5 months after the operation. A left mastectomy was performed and was diagnosed as borderline malignancy histologically. A second local recurrence was diagnosed 9 months after the left mastectomy. Tumor resection was performed, and the histological diagnosis was borderline. Two months after the third operation, a rapidly growing tumor appeared in her right breast. A right mastectomy was performed, and the histological findings indicated it was malignant phyllodes tumor. Eight months later, a locally recurrent tumor appeared and increased rapidly in size to 21 cm with necrosis and bleeding, along with thoracic invasion and multiple lung and bone metastases. The stromal MIB-1 index of the first, second, and third tumors of the left breast was 4.0%, 22.0%, and 25.6%, respectively, and the stromal MIB-1 index of the first and second tumor of the right breast was 23.0% and 21.6%, respectively. The MIB-1 index was correlated with the clinical grade of the malignancy in the phyllodes tumor.
