An Overview of Breast Fibroadenoma

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Breast fibroadenomas are the most common type of non-cancerous breast tumors. They're made up of stroma (fibrous connective tissues that support the mammary gland) and adenosis (lobes that have developed hyperplasia, which is an enlargement due to an increased rate of cellular reproduction).

Fibroadenomas can be felt during your monthly breast self-exam and will show up on mammograms and ultrasounds. Women in their 20s or 30s are most likely to develop a breast fibroadenoma, which may grow larger during pregnancy or breastfeeding (lactation.)


Most fibroadenomas are between one and five centimeters (cm) in diameter (0.39 inches to nearly two inches), but giant fibroadenomas can be the size of a small lemon, about 15 cm (5.9 inches). They are classified as either simple or complex, with simple fibroadenomas being more common in younger women and complex fibroadenomas more common as women age.

Roughly 10 percent of all fibroadenomas will disappear over time, and 20 percent will recur. If they don’t disappear, they usually stop growing when they reach two or three centimeters.

Typically, the only symptom is a small lump in the breast that you may discover during a self-exam. They feel firm, round, smooth, rubbery, and are movable. They are so mobile that women sometimes refer to them as “breast mice” because they tend to run away from your fingers.

These masses may feel tender or painful, especially right before your period, when they may swell due to hormonal changes.


The exact cause of fibroadenomas is unknown. They seem to be influenced by estrogen because they appear most often in premenopausal or pregnant women, or in women who are postmenopausal and taking HRT (hormone replacement therapy).

Most fibroadenomas change in size during your menstrual cycle, when your hormone levels are changing. Thus, during the menstrual cycle, the same adenoma can become more noticeable or it may shrink to the point where it is not readily palpable.

Risk Factors

Fibroadenomas are most common in women who are between 15 and 30 years old and in pregnant women. Fibroadenomas occur in 10 percent of all women but in 20 percent of African-American women.

Once you hit menopause, your risk goes down unless you're using estrogen therapy.


On a mammogram, fibroadenomas appear as round or oval smooth-edged masses. The outline will be clearly defined, not blurry, and not invading the adjacent spaces. Sometimes they are accompanied by coarse calcifications. Fibroadenomas can look like cysts or a well-contained tumor.

If you notice a lump during an exam or if an abnormality is seen on mammography, a breast ultrasound is usually the next step. This is especially true if you have dense breast tissue, which can make a lump more difficult to visualize. On ultrasound, a fibroadenoma will be easier to distinguish from other tissue because of the way it responds to sound waves. It will appear as a dark area, with a definite outline, homogeneous, round or oval, and may have smooth-edged bumps.

If ultrasound doesn’t give a definite result, the next study may be an MRI (magnetic resonance imaging).


While imaging tests may suggest a fibroadenoma, the conclusive diagnostic test is usually a breast biopsy.

Different types of biopsy procedures include fine-needle biopsy, cord-needle biopsy, and an open biopsy. The choice of type will depend on the characteristics of the lump, its location, and more.


In women older than age 35, a definitive diagnosis is more important. A breast biopsy may not be adequate for proper diagnosis because it only samples one part of a lump.

In recent years, doctors have learned that many breast lumps, both benign and cancerous, can be made up of different types of cells. There have been cases in which a breast biopsy has revealed a fibroadenoma, but after removal, when the entire mass is evaluated by a pathologist, cancer has been present as well.


It's important to distinguish between two types of fibroadenomas when choosing the best treatment options. That's due to a difference in breast cancer risk. Types of fibroadenomas include:

  • Simple: Most fibroadenomas are the simple types—there’s usually just one of them in your breast, with a definite border and very uniform cells. A simple fibroadenoma does not raise your risk for breast cancer.
  • Complex. Complex fibroadenomas are less common, and while they may have a definite border, it's what is inside this kind of fibroadenoma that makes it different. A complex fibroadenoma will not look organized and uniform like a simple one. Even though complex fibroadenomas don't become cancerous, they may contain a collection of small cysts, calcifications, enlarged breast lobules, papillomas and different kinds of hyperplasia. When atypical hyperplasia occurs, it can raise your risk of developing breast cancer.

Several different treatment options are available. Many factors may influence your choice of treatment, such as:

  • Whether you have a simple or a complex fibroadenoma
  • Your symptoms, especially discomfort and pain
  • Your emotional state, such as undue worry about it being cancer

Be open and honest with your doctor about what you're experiencing. Don't act like you're fine and then go home and stress about it.

Fibroadenoma treatment options include:

  • Watch and wait: Since fibroadenomas are not always troublesome and sometimes shrink on their own, just keeping an eye on their progress is the least invasive way to handle them.
  • Lumpectomy: Surgical removal can be done if you're worried about it staying there. Depending on the relative size of this lump and your breast, a lumpectomy may cause a change in your breast's size or shape. New fibroadenomas may grow in the neighborhood of the first lump, so you should know that surgery is not a guarantee that you'll never have another fibroadenoma. On the other hand, your fibroadenoma can be carefully examined by the pathology lab to make sure the diagnosis was correct.
  • Laser ablation: In your surgeon's office, an ultrasound-guided laser device is used to destroy the fibroadenoma, leaving behind only a tiny scar, no sutures, and no change in breast shape. You don't need general anesthesia and it's usually an out-patient procedure, which means no hospital stay.
  • Cryoablation: This is a fast, efficient way to freeze a fibroadenoma. In one office visit, the doctor simply freezes the lump so that healthy tissue can take over. This procedure takes less than 30 minutes and results in a tiny scar.
  • Radiofrequency ablation (RFA): This is a way to remove fibroadenomas without resorting to a lumpectomy. Using local anesthesia and ultrasound guidance, a six to eight-millimeter cut is made above the fibroadenoma. Through this cut, a surgical wand is inserted and then tipped by a knife that is heated by radiofrequency current. This helps cut through the breast tissue without causing much bleeding. Once it reaches the target, small wires and robotic arms capture the fibroadenoma and extract it.
  • Mammotome: Breast biopsy systems can now be used as a fairly non-invasive way to remove fibroadenomas. In less than an hour, and under local anesthesia, a six-millimeter (1/4 inch) cut is made over the fibroadenoma. Then with ultrasound guidance, a Mammotome probe is threaded into the lump, which vacuums out sections of the tissue. Recovery is quick and your scar will be quite small.
  • High-frequency focused ultrasound (HFU): This is a relatively new treatment that has been used for fibroadenomas, and sometimes, even for breast cancer. HFU appears to cause the selective destruction of deep tissues without damaging surrounding healthy tissue.

    For pain that may be due to an adenoma, home remedies that help some people include over-the-counter pain medications, heat, castor oil, and ginger tea. Remember that these approaches don't replace proper tests and the above treatments.

    Complementary and Alternative Medicine

    Herbal tonics, teas, ointments, or homeopathic pills are sometimes touted as effective treatments, but few controlled studies have looked into these remedies.

    One example of this kind of treatment is the supplement blend called Fibrosolve, which claims to be a "noninvasive, risk-free treatment option for fibroadenomas." However, there's little-to-no evidence to back up these claims. While many of the ingredients may be generally considered good for you, consider this risk: If a fibroadenoma is hiding breast cancer and you don't have it removed, cancer may remain undetected and risk your future health, and even your life.

    It's important to note that without a biopsy, and possibly removal of the fibroadenoma, there is always a chance that breast cancer could be missed, and therefore treatment delayed.

    A Word From Verywell

    Remember that the only way to get a conclusive diagnosis of a fibroadenoma is with a breast biopsy. While this can cause some anxiety, it may also be the best way to reduce anxiety as well, since it can assure you that the lump is not cancerous.

    Keep in mind that there are many types of breast lumps, only one of which is a fibroadenoma. If you have a breast lump, even if you feel certain that it is only a fibroadenoma, get it checked out. Too many people have dismissed a breast lump as being "only" a fibroadenoma, only later to learn that they actually had breast cancer.

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