A cystosarcoma phyllodes or phyllodes tumor is a rare form of tumor occurring in the breast, or even more rarely occurring in the prostate gland. Most often the phyllodes tumor is associated with breast cancer, though many of these tumors are not cancers. They may be benign, but they have a quick growth rate, which means that if ignored they can grow large enough to need removal by mastectomy.
Phyllodes tumors tend to invade the connective tissue of the breast, but they don’t usually occur in the ducts of the breast. They are most likely to develop in women who have not yet reached menopause, with the most phyllodes tumors noted in women between the ages of 40-50. A much younger woman can have one of these tumors, and cases have occurred in teenage girls, though this is rarer. What is often most apparent about these tumors is they can change in size quickly, and it’s not uncommon for growth to be noticeable and for these tumors to become very large in a matter of weeks or months.
There is differing information on whether a phyllodes tumor is likely to be cancerous. Some sources like the Merck Manual cite that approximately 50% of these tumors are malignant. Other equally reputable sources claim that about 80% are benign. It does seem that there are a high rate of benign phyllodes tumor cases, and that the higher estimate of noncancerous forms may be more accurate.
If a phyllodes tumor is suspected, women will typically need to undergo a needle or open surgical biopsy. This helps test the tumor for possible malignancy, and it may be then be considered benign, borderline or malignant. This rating determines treatment. Cancerous (malignant) tumors, and borderline ones might mean undergoing chemotherapy or radiation after mastectomy. Benign tumors still need to be removed. If the benign tumor is caught early, removal may be done in the form of a lumpectomy, but if the tumor is malignant or borderline, lumpectomies tend not to be preferable. About 20% of women will have a recurrence of the Phyllodes tumor.
These tumors are exceptionally rare, and account for only 1% of all breast cancer cases. They are even more rare when they occur in the prostate gland and like the breast type, they can be either malignant or benign. Unfortunately, the phyllodes tumor of the prostate can get even larger than those in the breasts before they’re noticed, since this isn’t an area of the body that men can check by themselves for evidence of lumps or tumors. As with treatment when such tumors occur in the breast, it’s recommended that those occurring in the prostate be removed immediately and checked for potential malignancy.