Fibroadenomas (fy-broe-ad-uh-NO-muhz) are solid, noncancerous breast lumps that occur most often in women between the ages of 15 and 35.
A fibroadenoma might feel firm, smooth, rubbery or hard and has a well-defined shape. Usually painless, it might feel like a marble in your breast, moving easily under your skin when examined. Fibroadenomas vary in size, and they can enlarge or shrink on their own.
Fibroadenomas are among the most common noncancerous (benign) breast lumps in young women. Treatment might include monitoring to detect changes in size or feel, a biopsy to evaluate the lump or surgery to remove it.
Fibroadenomas are solid breast lumps that usually are:
Round with distinct, smooth borders
Firm or rubbery
You can have one or many fibroadenomas in one or both breasts.
When to see a doctor
In healthy women, normal breast tissue often feels lumpy. Make an appointment with your doctor if:
You detect a new breast lump
You notice other changes in your breasts
A breast lump you've had checked before has grown or otherwise changed and appears to be separate from the surrounding breast tissue
The cause of fibroadenomas is unknown, but they might be related to reproductive hormones. Fibroadenomas occur more often during your reproductive years, can become bigger during pregnancy or with use of hormone therapy, and might shrink after menopause, when hormone levels decrease.
Types of fibroadenomas
In addition to simple fibroadenomas, there are:
Complex fibroadenomas. These can contain changes, such as an overgrowth of cells (hyperplasia) that can grow rapidly. A pathologist makes the diagnosis of a complex fibroadenoma after reviewing the tissue from a biopsy.
Juvenile fibroadenomas. This is the most common type of breast lump found in girls and adolescents between the ages of 10 and 18. These fibroadenomas can grow large, but most shrink over time, and some disappear.
Giant fibroadenomas. These can grow to larger than 2 inches (5 centimeters). They might need to be removed because they can press on or replace other breast tissue.
Phyllodes tumor. Although usually benign, some phyllodes tumors can become cancerous (malignant). Doctors usually recommend that these be removed.
Most fibroadenomas don't affect your risk of breast cancer. However, your breast cancer risk might increase slightly if you have a complex fibroadenoma or a phyllodes tumor.
During a clinical breast exam, your doctor will check both breasts for lumps and other problems. Some fibroadenomas are too small to feel, so they can only be discovered in imaging tests.
If you have a lump that can be felt (palpable), your doctor might recommend certain tests or procedures, depending on your age and the characteristics of the lump.
Tests to evaluate the breast lump
Diagnostic mammography. Mammography uses X-rays to produce an image (mammogram) of suspicious areas in your breast tissue. A fibroadenoma might appear on a mammogram as a breast mass with smooth, round edges, distinct from surrounding breast tissue.
Breast ultrasound. This technology uses sound waves to produce pictures of the inside of the breast. Your doctor might recommend a breast ultrasound in addition to a mammogram to evaluate a breast lump if you have dense breast tissue.
For women younger than 30 who have a breast lump, the doctor likely will order a breast ultrasound first to evaluate the lump.
If a mammogram indicates that you have a breast lump or other abnormality, a breast ultrasound might be used to further assess the lump. A breast ultrasound can help your doctor determine whether a breast lump is solid or filled with fluid. A solid mass is more likely a fibroadenoma; a fluid-filled mass is more likely a cyst.
Procedures to evaluate the breast lump
Fine-needle aspiration. Through a thin needle inserted into your breast, your doctor attempts to withdraw the contents of the breast lump. If fluid comes out, the lump is likely a cyst.
Core needle biopsy. A radiologist with guidance from an ultrasound usually performs this procedure. The doctor uses a needle to collect tissue samples from the lump, which go to a lab for analysis.
In many cases, fibroadenomas require no treatment. However, some women choose surgical removal for their peace of mind.
If your doctor is reasonably certain that your breast lump is a fibroadenoma — based on the results of the clinical breast exam, imaging test and biopsy — you might not need surgery.
You might decide against surgery because:
Surgery can distort the shape and texture of the breast
Fibroadenomas sometimes shrink or disappear on their own
The breast has multiple fibroadenomas that appear to be stable — no changes in size on an ultrasound compared to an earlier ultrasound
If you choose not to have surgery, it's important to monitor the fibroadenoma with follow-up visits to your doctor for breast ultrasounds to detect changes in the appearance or size of the lump. If you later become worried about the fibroadenoma, you can reconsider surgery to remove it.
Your doctor might recommend surgery to remove the fibroadenoma if one of your tests — the clinical breast exam, an imaging test or a biopsy — is abnormal or if the fibroadenoma is extremely large, gets bigger or causes symptoms.
Procedures to remove a fibroadenoma include:
Lumpectomy or excisional biopsy. In this procedure, a surgeon removes breast tissue and sends it to a lab to check for cancer.
Cryoablation. Your doctor inserts a thin, wand-like device (cryoprobe) through your skin to the fibroadenoma. A gas is used to freeze and destroy the tissue.
After a fibroadenoma is removed, it's possible for one or more new fibroadenomas to develop. New breast lumps need to be assessed with a mammogram, ultrasound and possibly biopsy — to determine if the lump is a fibroadenoma or might become cancerous.
Preparing for an appointment
You're likely to start by seeing your family doctor or gynecologist. Here's some information to help you get ready for your appointment.
What you can do
When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet. Make a list of:
Your symptoms, including any that seem unrelated to your breast changes, and when they began
Key personal information, including your and your family's medical history and whether there's a history of breast cancer in your family
All medications, vitamins or other supplements you take, including doses
Questions to ask your doctor
Bring a family member or friend along, if possible, to help you remember the information you're given.
For a fibroadenoma, basic questions to ask your doctor include:
What might this lump be?
What tests do I need? Do I need to do anything special to prepare for them?
What treatments are available?
Do you have brochures or other written materials about this topic? What websites do you recommend?
Don't hesitate to ask other questions.
What to expect from your doctor
Your doctor is likely to ask you a number of questions, including:
When did you notice the lump? Has its size changed?
Does the size of the lump change around your menstrual periods?
Have you or other family members had breast problems?