Abstract
We report the case of a 50-year-old woman who presented with a 3-cm tumor in her right breast. Mammography showed an oval distinct tumor in the right breast. Ultrasonography showed a homogeneous, low-echoic mass and a clear boundary. On core needle biopsy, a diagnosis of dermatofibrosarcoma protuberans was suggested because the tumor was mainly composed of CD34-positive proliferated spindle cells. The patient underwent right lumpectomy, including a skin tumor just above and just below the pectoralis major muscle. Pathological examination showed an increased amount of proliferated spindle cells, with myxomatous changes. The tumor cells were positive for α-SMA, and the CD34-positive range was narrow. Myxofibrosarcoma was diagnosed.
