Phyllodes Tumor of the Breast With Malignant Melanoma Component: A Case Report

Phyllodes tumors of the breast display a wide variation in histological appearance and are classified into benign, borderline, and malignant categories based on a combination of histological parameters. These tumors may include a malignant heterologous component that is believed to originate through a process of multidirectional differentiation from a cancer stem cell. In these cases, the tumor is classified as a malignant phyllodes tumor. Among the heterologous elements that have been described in malignant phyllodes tumors are rhabdomyosarcoma, chondrosarcoma, osteosarcoma, liposarcoma and angiosarcoma. We present the first case of a phyllodes tumor with a malignant melanoma component in the breast of a 71-year-old lady, discussing the clinical implications of this diagnosis.