Phyllodes tumors often grow quickly, but they rarely spread outside of the breast. Most phyllodes tumors are benign, some are borderline, and fewer are malignant. All three kinds require surgery to help prevent their recurrence.
Phyllodes tumors can happen at any age, but tend to develop in women in their 40s. Benign phyllodes tumors are usually diagnosed at a younger age than the malignant type. And, as with many forms of breast cancer, phyllodes tumors are extremely rare in men.
Signs and symptoms
A breast lump that is not painful is the most common symptom of the rare phyllodes tumor.
The lump is easy for a woman herself or a doctor to feel when examining the breasts. They often appear in the upper, outer quadrant of the breast.
Both malignant and benign phyllodes tumors tend to grow quickly. Over the course of a few weeks or months, the tumor can grow to 2-3 centimeters (cm) or bigger. The average tumor size is around 5 cm, but they can be several times larger.
The lump is usually not painful. In some cases, a visible bulge is seen as it begins to push against the skin of the breast. In more advanced cases, a phyllodes tumor may cause an ulcer to form on the breast skin. This can happen regardless of whether the tumor is benign, borderline, or malignant.
The phyllodes tumor may also expand the veins under the skin, causing portions of the breast to appear blue.
Phyllodes tumors are rare. Doctors are less likely to encounter them compared with other tumors, which make diagnosis more difficult.
Also, a phyllodes tumor can look like a type of solid breast growth called a fibroadenoma. A fibroadenoma is a benign, growing lump of normal breast cells. It is the most common breast mass and is seen in younger women.
There are two distinctions between fibroadenomas and phyllodes tumors.
Firstly, phyllodes tumors tend to grow more quickly than fibroadenomas.
Secondly, phyllodes tend to develop about 10 years later in life, when women are in their 40s. In contrast, women often develop fibroadenomas when they are in their 30s.
These two differences can help doctors determine if the growths are a result of phyllodes tumors or fibroadenomas.
As with many tumors, diagnosing phyllodes tumors involves several steps:
- The woman or her doctor may be able to feel the lump in the breast, which is the first step in diagnosis.
- After finding a lump, the doctor may order a mammogram to obtain X-ray images of the breast. The images will also help to locate the lump.
- An MRI is often used to get additional images of the tumor. These images help with surgery.
On a mammogram, a phyllodes tumor appears as a roundish mass with well-defined edges. In some cases, the tumor may appear to have rounded lobes inside it. Additional tests will still be needed to determine what it is.
If initial tests prove to be inconclusive then a doctor may order a biopsy to diagnose a phyllodes tumor.
Additional imaging may be done with an ultrasound that uses echoed sound waves to create an image. Phyllodes tumors resemble well-defined masses, with some cysts inside when viewed through an ultrasound.
As with diagnosing other tumors and cancers, a doctor may order a biopsy, to take samples of the tumor to look at under a microscope. A biopsy is the only way for a doctor to determine absolutely that the growth is a phyllodes tumor.
A doctor will carry out either a core needle biopsy or an excisional biopsy. A core needle biopsy is where a hollow needle takes a sample of the tumor through the skin. An excisional biopsy removes the whole tumor.
Some researchers believe the best course of action is to use an excisional biopsy if the lump is believed to be a phyllodes tumor. This is because examining the whole tumor is often necessary to make a correct diagnosis. The core needle biopsy sample may not offer enough evidence to confirm it is a phyllodes tumor.
Once a biopsy is taken, a pathologist examines the tissue under a microscope to make a final diagnosis. In this process, the pathologist will also classify the phyllodes tumor as benign, borderline, or malignant.
For a benign tumor, a pathologist will often see:
- well-defined edges
- cells that do not divide rapidly
- connective tissue cells that still look normal
- no "overgrowth" of connective tissue cells
For a malignant tumor, a pathologist will often see:
- not well-defined edges
- cells that divide rapidly
- connective tissue cells with an abnormal appearance
- an overgrowth of connective tissue cells
For borderline cases, a pathologist will see symptoms that fall between the benign and malignant forms.
The main difference between the types of tumor is that malignant tumors, particularly those with lots of connective tissue overgrowth, may recur more quickly. Malignant tumors are also more likely to recur outside the breast.
The only way to effectively treat a phyllodes tumor is to remove the growth entirely. Surgery helps prevent future tumors and complications from the existing tumor.
The label benign may help put a woman at ease about the tumor not being cancerous or harmful. However, benign phyllodes tumors still require treatment as they can get large.
The growth will eventually create a visible lump on the breast and may break through the skin, causing pain and discomfort, if left untreated.
After treatment and removal, there may be no further complications as the risk of the tumor spreading is low for this type of cancer.
After treatment for a phyllodes tumor, a woman should have limited issues. Removal usually results in no further complications except minor pain from the procedure, and the need to take it easy.
Benign phyllodes tumors have less chance of recurring than malignant ones. A doctor will check frequently for recurrence, with the most likelihood being within a year or two.
In cases of malignant tumors, a doctor may recommend additional treatment options should a tumor come back. These may include breast removal surgery or radiation.
The risk for the tumor spreading beyond the breast is very low for this type of cancer.
Effect on cancer risk
Even in cases of malignant phyllodes tumors, there is a limited risk of the cancer spreading and no noticeable impact on future breast cancers or cancers outside the breast.
The recurrence of the tumor is higher with malignant types than benign. However, it is an easier tumor to treat and remove than other types.