Phyllodes Tumors

Medically Reviewed by Sabrina Felson, MD on August 23, 2022
Written by Susan Bernstein
4 min read

Phyllodes tumors are a rare type of breast growth. Less than 1% of all breast tumors are this type. Most are not cancer, called benign. But about 25% of these tumors are cancerous (or malignant). Some are borderline, a mix of benign and cancerous.

Phyllodes tumors start in your breast’s stromal, or connective, tissue. Phyllodes means “leaflike.” That’s because as they grow, the tumors have the shape of a leaf.

All phyllodes tumors may grow. But they rarely spread beyond your breast. You can have surgery to remove them, but they might come back.

A phyllodes tumor feels like a lump in your breast. It usually isn’t painful. You might notice the lump on your own, or your doctor may feel it during a routine exam.

Phyllodes tumors can grow to 3 centimeters wide -- a little more than an inch -- in just a few weeks or months. They often grow quickly, even if they’re benign. You may notice them bulging through your skin. Sometimes, they can stretch your skin or cause an ulcer on your breast.

Experts don’t know what causes phyllodes tumors. Women who have a rare genetic disease called Li-Fraumeni syndrome are more likely to have them. They rarely affect men.

Women of any age can get phyllodes tumors, but they’re most common in your 40s.

Phyllodes tumors and breast cancer risk

A benign phyllodes tumor doesn’t affect your chances of getting breast cancer later on.

Tests can tell whether a lump is a phyllodes tumor.

  • Mammogram. Your doctor may suspect a phyllodes tumor because of something they see on a regular mammogram or ultrasound. It will show detailed images of the lump. A phyllodes tumor has a clearly defined round or oval shape. There may be tiny flecks of calcium inside it.
  • Ultrasound. This test uses sound waves to show pictures inside your body. The doctor will use it to see if the lump is clearly defined and round.
  • Needle biopsy. Your doctor may do a core needle biopsy of your lump to confirm your diagnosis. They’ll take a small sample of tissue with a hollow needle and use a microscope to check for signs of cancer.
  • Excisional biopsy or lump removal. Most people need this procedure to get a diagnosis. Your surgeon will remove the whole lump and examine the tissue. This biopsy can show if your tumor is benign, borderline cancer, or malignant.

All phyllodes tumors, even benign ones, require surgery. If your tumor is malignant, you may need more aggressive surgery and other treatment.

Surgery

There are a few options:

Wide excision surgery removes the phyllodes tumor along with some of the healthy breast tissue around it. This helps prevent your tumor from growing back.

Lumpectomy is surgery to remove the tumor and at least 1 centimeter of healthy breast tissue around it. After surgery, a specialist called a pathologist looks at the tissue under a microscope. If they aren’t sure your surgeon removed all the tumor cells, you may need more surgery to take out a wider area of healthy breast tissue.

Mastectomy is an option if your tumor is malignant or large, or if your breast is too small for easy removal with a lumpectomy. In this procedure, the surgeon removes part or all of your breast. You can have breast reconstruction surgery at the same time or later on.

Usually, your doctor won’t need to remove any lymph nodes from your armpit near your breast, because phyllodes tumors rarely spread there.

Radiation or chemotherapy

If you have a malignant phyllodes tumor that hasn’t spread beyond your breast, the doctor may order radiation therapy. Doctors sometimes prescribe chemotherapy drugs if a phyllodes tumor has spread beyond the breast, but this is rare.

Follow-up treatment

Because phyllodes tumors can return, you need careful follow-up after your surgery.

  • Within 4 to 6 months of your surgery, see your doctor for a breast exam, mammogram, and ultrasound. The doctor may also suggest an MRI, an imaging test that uses a magnetic field to make pictures of your body.
  • Get regular mammograms and/or ultrasounds on the schedule your doctor suggests.

If your phyllodes tumor was malignant, you may need regular CT scans of your chest and abdomen for 5 years after your surgery.

Your outlook is excellent if you had a benign tumor removed with surgery. Treatment often cures malignant phyllodes tumors, but they’re more likely to grow back. They can spread beyond your breast to your lungs. Women with malignant phyllodes tumors still have a high survival rate.