The cystosarcoma phyllodes is a rare and infrequently recurring tumor of the breast. Here we present a recurrent cystosarcoma phyllodes tumor during pregnancy involving the whole breast tissue and treated by mastectomy and silicon implantation. The fine needle aspiration cytology revealed a benign cytology-fibroadenoma and the 5.5 cm tumor was locally excised 3 years ago. The pathologic diagnosis was benign phyllodes tumor. During pregnancy, the tumor recurred and involved the whole breast. Mastectomy and reconstruction with silicon implant was the treatment choice at this time. The pathology of the mastectomy specimen was malignant phyllodes tumor. The phyllodes tumors should be locally excised with a wide margin although they are benign in nature. Mastectomy and reconstruction may be recommended as a safe surgical treatment modality in giant phyllodes tumors of the breast.
Keywords: cystosarcoma phyllodes, mastectomy, silicon implantation