Phyllodes Tumors of the Breast

Phyllodes tumors (FILL-odes or full-OH-deez) can also be spelled phylloides tumors (full-OY-deez). These are rare breast tumors that start in the connective (stromal) tissue of the breast.

Phyllodes tumors are most common in women in their 40s, but women of any age can have them. Women with Li-Fraumeni syndrome (a rare, inherited genetic condition) have an increased risk for phyllodes tumors.

Most phyllodes tumors are benign (not cancer), but about 1 out of 4 of these tumors are malignant (cancer).

Diagnosis

The tumors are usually felt as a painless breast lump, but some may hurt. They tend to grow quickly and stretch the skin. Sometimes they are seen first on an imaging test (like an ultrasound or mammogram), in which case they’re often hard to tell apart from fibroadenomas. The diagnosis can often be made with a core needle biopsy, but sometimes the entire tumor needs to be removed (during an excisional biopsy) to know for sure that it’s a phyllodes tumor, and whether it's malignant or not.

How do phyllodes tumors affect your risk for breast cancer?

Having a benign phyllodes tumor does not affect your breast cancer risk, but you may be watched more closely and get regular imaging tests, because these tumors can come back after surgery.

Treatment

Breast-conserving surgery (lumpectomy or partial mastectomy), in which part of the breast is removed, is typically the main treatment. Phyllodes tumors can sometimes come back in the same place if they’re removed without taking enough of the normal tissue around them. For this reason, a margin of normal breast tissue around the tumor is taken out as well. Mastectomy (removal of the entire breast) may be needed if a cancer-free margin of normal breast tissue cannot be taken out with the tumor.

If the phyllodes tumor is cancer, a wider area of normal tissue will be removed along with the tumor. Or the entire breast might be removed with mastectomy. Radiation therapy might be given to the area after surgery, especially if it’s not clear that all of the tumor was removed.  Malignant phyllodes tumors are different from the more common types of breast cancer. They are less likely to respond to some of the treatments commonly used for breast cancer, such as hormone therapy or the chemotherapy drugs normally used for breast cancer. Phyllodes tumors that have spread to other parts of the body are often treated more like sarcomas (soft-tissue cancers) than breast cancers.

Because these tumors can come back, close follow-up with frequent breast exams and imaging tests are usually recommended after treatment.

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Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: September 10, 2019 Last Revised: September 10, 2019

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