Benign Phyllodes Tumor Mimicking a Malignancy in a Turner Syndrome Woman with Hormone Replacement Therapy: A Case Report

Phyllodes tumor of the breast is a relatively rare fibroepithelial tumor. Turner syndrome is a condition that affects approximately 50 per 100,000 females and includes total or partial absence of one X chromosome in all or part of the cells, reduced final height, absence of female sex hormone, and infertility. In this case report, we describe the first case of a benign phyllodes tumor mimicking a malignancy at breast US in a 26-year-old woman with Turner syndrome who had been undergoing hormone replacement therapy.