Gigantic cystosarcoma phyllodes in a man with gynecomastia.

A 70-year-old man had a breast tumor for 50 years. The tumor, which weighed 8.6 kg, proved to be a malignant cystosarcoma phyllodes. It was successfully removed by a simple mastectomy with low axillary dissection, and a skin graft was performed. The lesion was associated with gynecomastia, and it is believed to have represented a cystosarcomatous transformation of a giant fibroadenoma.