Signs and symptoms of phyllodes tumors
The most common symptom of a phyllodes tumor is a breast lump that you or your doctor can feel while examining the breasts. Phyllodes tumors tend to grow quickly, within a period of weeks or months, to a size of 2-3 cm or sometimes larger. This rapid growth does not automatically mean the phyllodes tumor is malignant; benign tumors can grow quickly, too. The lump is usually not painful. If left unchecked, the lump can create a visible bulge as it pushes against the skin. In more advanced cases — whether benign, borderline, or malignant — a phyllodes tumor can cause an ulcer or open wound to form on the breast skin.
Diagnosis of phyllodes tumors
Like other less common types of breast tumors, phyllodes tumors can be difficult to diagnose because doctors don't encounter them all that often. A phyllodes tumor also can look like a more common type of benign breast growth called a fibroadenoma. A fibroadenoma is a solid, growing lump of normal breast cells that is the most common kind of breast mass, especially in younger women.
Two key differences between fibroadenomas and phyllodes tumors are that phyllodes tumors tend to grow more quickly and develop about 10 years later in life — in the 40s as opposed to the 30s. These differences can help doctors distinguish phyllodes tumors from fibroadenomas.
Diagnosing phyllodes tumors usually involves a combination of steps:
- A physical examination of the breasts. Your doctor may be able to feel the lump in the breast, or you may feel it yourself during a breast self-exam.
- A mammogram to obtain X-ray images of the breast and locate the tumor. On a mammogram, a phyllodes tumor appears as a large round or oval mass with well-defined edges. Sometimes the tumor might look like it has rounded lobes inside it. Calcifications can show up as well. Calcifications are tiny flecks of calcium — like grains of salt — in the soft tissue of the breast. Your doctor likely will need to do additional testing to confirm that the lump is a phyllodes tumor.
- Ultrasound to obtain sound-wave images of the breast. The images form as the sound waves are "echoed back" by the tissue. On ultrasound, phyllodes tumors look like well-defined masses with some cysts inside of them.
- MRI to obtain additional images of the tumor and help in planning surgery.
Biopsy to take samples of the tumor for examination under a microscope. Although imaging tests are useful, biopsy is the only way to tell if the growth is a phyllodes tumor. Your doctor can perform one of two procedures:
- core needle biopsy, which uses a special hollow needle to take samples of the tumor through the skin
- excisional biopsy, which removes the entire tumor
Some experts believe it is better to use excisional biopsy if a phyllodes tumor is suspected. Examining the whole tumor is often necessary to make the right diagnosis. The smaller tissue samples taken during core needle biopsy may not be enough to confirm that a lump is a phyllodes tumor.
A pathologist then examines the tumor tissue under a microscope to make the diagnosis. He or she also classifies the phyllodes tumor as benign, borderline, or malignant. In a benign tumor:
- the edges are well-defined
- the cells are not dividing rapidly
- the stromal cells (connective tissue cells) still look somewhat like normal cells
- there is not an "overgrowth" of stromal cells — there are epithelial cells (the types of cells that line the ducts and lobules) as well
In a malignant tumor:
- the edges are not well-defined
- the cells are dividing rapidly
- the stromal cells have an abnormal appearance
- there is an overgrowth of stromal cells, sometimes with no epithelial cells present at all
Phyllodes tumors are called "borderline" if their features fall somewhere in between these two descriptions.
The label "benign" often makes people think that a condition is not harmful and may not require treatment. But benign phyllodes tumors, like malignant ones, can grow to be large in size, creating a visible lump on the breast and perhaps even breaking through the skin, causing pain and discomfort. This is why both benign and malignant tumors require treatment. The main difference between them is that malignant phyllodes tumors, especially those with lots of stromal overgrowth, may recur more quickly and have a greater likelihood of recurring outside the breast.