Cancerous Phyllodes Tumors of the Breast
Phyllodes tumors are rare and make up fewer than 1% of all breast tumors. Phyllodes tumors start in the stroma, the connective tissue of the breast.
The name comes from the Greek word for leaf because the cells grow in a pattern that looks like a leaf. Other names for phyllodes tumors are phylloides tumors and cystosarcoma phyllodes.
Most phyllodes tumors are benign (non-cancerous), a small percentage are malignant (cancerous), and a few are called borderline because they have characteristics that are in between benign and malignant.
Phyllodes tumors are most commonly diagnosed in women in their 40s, but they can develop at any age. Women with Li-Fraumeni syndrome, a rare inherited condition that may cause a higher risk of of a number of cancers, including breast cancer, have a higher risk of developing phyllodes tumors.
Cancerous phyllodes tumors are a form of breast cancer, but are very different from invasive ductal carcinoma, cancer that starts in the milk ducts.
Phyllodes tumors of the breast symptoms
The most common symptom of a phyllodes tumor is a breast lump. It doesn’t matter if a phyllodes tumor is non-cancerous or cancerous, it tends to grow fairly quickly and stretch the skin. Phyllodes tumors can be very small or very large — they range in size from 1 centimeter to 45 centimeters. In some cases, the lump may be painful.
Diagnosis of phyllodes tumors of the breast
Diagnosing a phyllodes tumor usually involves a combination of procedures, including:
When first found by a mammogram, it can be hard to tell the difference between a phyllodes tumor and a fibroadenoma, the most common type of benign breast tumor.
In some cases, your doctor will be able to make a diagnosis after a biopsy, but in other cases, the entire tumor will need to be removed before your doctor can tell what kind of tumor it is and whether it’s cancerous or not.
Benign phyllodes tumors have cells with well-defined edges and the cells are not dividing rapidly.
Cancerous phyllodes tumors have cells that are dividing rapidly and the stromal cells look abnormal.
Borderline phyllodes tumors have characteristics that are between benign and malignant.
Phyllodes tumors of the breast treatment
Whether the phyllodes tumor is cancerous, benign, or borderline, the first treatment is always surgery:
lumpectomy is the most common surgery done to remove a phyllodes tumor; the tumor, plus a margin of healthy, cancer-free tissue larger than 1 centimeter around it is removed
mastectomy may be done if a margin of cancer-free tissue can’t be removed with the tumor during lumpectomy
It’s rare for phyllodes tumors to spread to the lymph nodes, so lymph node surgery usually isn’t needed.
If the phyllodes tumor is cancerous, radiation therapy may be given to the area where the tumor was after surgery.
Cancerous phyllodes tumors don’t usually respond well to common breast cancer treatments, such as hormonal therapy and chemotherapy. Still, if the phyllodes tumor has spread to other parts of the body, you’ll usually be treated with chemotherapy.
Survivorship care after treatment for phyllodes tumors of the breast
Phyllodes tumors can come back, either in the breast, if you had lumpectomy, or in the skin and underlying tissues of the breast, if you had mastectomy. In very, very rare cases, phyllodes tumors may come back in a part of the body away from the breast.
So you and your doctor will develop a survivorship care plan that will likely include more frequent screening, including:
breast physical exam every six to 12 months
a mammogram at least every 12 months; your screening plan may include both a mammogram and breast MRI each year, done six months apart
Phyllodes tumors can come back in the breast, which doctors call local recurrence. Local recurrence is more common for cancerous phyllodes tumors than it is for benign and borderline tumors. Still recurrence rates depend on the characteristics of the tumor and treatments. Overall, local recurrence rates for all three types of phyllodes tumors are about 20%.
Distant recurrence, which means the phyllodes tumor comes back in an area of the body away from the breast, such as the lungs or bones, is rare and usually happens only with cancerous phyllodes tumors.
— Last updated on February 6, 2025 at 8:39 PM