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Phyllodes Tumors of the Breast
Phyllodes tumors (or phylloides tumors) are rare breast tumors that start in the connective (stromal) tissue of the breast, not the ducts or glands (which is where most breast cancers start). Most phyllodes tumors are benign and only a small number are malignant (cancer)
Phyllodes tumors are often divided into 3 groups, based on how they look under a microscope:
- Benign (non-cancerous) tumors account for more than half of all phyllodes tumors. These tumors are the least likely to grow quickly or to spread.
- Borderline tumors have features in between benign and malignant (cancerous) tumors.
- Malignant (cancerous) tumors account for about 1 in 4 phyllodes tumors. These tend to grow the fastest and are the most likely to spread or to come back after treatment.
Who is most at risk for phyllodes tumors?
Phyllodes tumors are most common in women in their 40s, but women of any age can have them. Men can also have them.
Women with a rare, inherited genetic condition called Li-Fraumeni syndrome have an increased risk for phyllodes tumors.
Symptoms and diagnosis of phyllodes tumors
Phyllodes tumors are usually felt as a firm, painless breast lump. But some may hurt. They tend to grow large fairly quickly, and they often stretch the skin.
Sometimes these tumors are seen first on an imaging test like an ultrasound or mammogram. In these cases, it can be hard to tell them apart from fibroadenomas.
The diagnosis can sometimes be made with a core needle biopsy. But often the entire tumor needs to be removed with an excisional biopsy to know for sure if 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.
- Having a malignant phyllodes tumor means you have a type of breast cancer. However, it does not affect your risk of getting other, more common types of breast cancer.
Even if you’ve had a benign phyllodes tumor, you will likely be watched more closely and get regular imaging tests after treatment. This is because these tumors can sometimes come back after surgery.
Do phyllodes tumors need to be treated?
Phyllodes tumors typically need to be removed completely.
Treating benign phyllodes tumors
If the tumor is found to be benign after an excisional biopsy, typically no other treatment is needed. If the whole tumor was not removed with the biopsy, your care team may recommend surgery to remove it fully.
Treating borderline or malignant phyllodes tumors
If the tumor is borderline or malignant, an area of normal tissue around the tumor is usually removed along with the tumor. This is called the tumor margin. The tumor might be removed with breast-conserving surgery. This removes only the unhealthy areas with a lumpectomy or partial mastectomy. Or the entire breast might be removed with a mastectomy, especially if the tumor is large and a margin of normal breast tissue can't be taken out with breast-conserving surgery.
Radiation therapy might be given to the area after surgery, especially if it’s not clear that all of the tumor was removed.
Treating tumors that have spread
Malignant phyllodes tumors are different from more common types of breast cancer. Hormone therapy is not helpful for these tumors. The chemotherapy drugs used for these tumors are usually not the same as those used for other breast cancers. Phyllodes tumors that have spread to other parts of the body are often treated more like sarcomas (soft-tissue cancers) than breast cancers. The most common chemotherapy drugs used are doxorubicin and ifosfamide. Other treatments might be used as well, depending on the stage and spread of the tumor.
Follow up after treatment
Even benign phyllodes tumors can sometimes come back in the same place. Because of this, close follow-up with frequent breast exams and imaging tests are usually recommended after treatment.
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The 黑料大湿Posts Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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Last Revised: June 15, 2022
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