Primary squamous cell carcinoma of breast in background of phyllodes tumor--a case report.

Primary squamous cell carcinoma of the breast (PSCCB) is a rare and generally aggressive malignancy constituting < 0.1% of invasive breast cancers. This report describes a case of primary squamous cell carcinoma of the breast that emerged in association with a phyllodes tumor. Our patient, a 59-year-old female, presented with a rapidly growing 9x12 cm breast mass. She underwent modified radical mastectomy followed by chemotherapy with carboplatin and docetaxel. She is free of disease one year after diagnosis. Clinicians should be aware of the aggressive behavior of this tumor, and adequate investigation should be done to rule out metastasis from another primary site.