If a clinical breast exam identifies a breast lump, calcifications that look suspicious are seen on a mammogram, or an ultrasound or MRI identifies an area that looks abnormal, typically the next step is a biopsy.

A biopsy is a sample of cells or tissue. The biopsy is sent to a cytologist or pathologist who will look at it closely under a microscope and may also perform tests on the cells to learn more about them.

Either a fine-needle biopsy or a core biopsy will be done to get the cell or tissue sample. A fine-needle (like the kind used to draw blood) biopsy takes only a few cells out of the lump; a larger-needle biopsy, called a core, cuts a small piece out of the lump. The biopsy can be done in a doctor’s office, but it is typically done in a room where the radiologist or surgeon can use ultrasound to make sure the needle biopsies the right area.

After a biopsy a cell or tissue sample is sent to the lab for examination

A core biopsy should always be done if a woman has a suspicious lump that is palpable (can be felt with fingertips) and/or one that the radiologist classified as BI-RADS 4 or 5.

After the core biopsy, a small metal clip is used to permanently mark the site of the biopsy and a mammogram is usually obtained to show the clip position. The clip will not set off metal detectors in the airport but will show up on later breast imaging. It is important to have a clip placed to mark the spot that was biopsied in case there is no longer any visible lesion on imaging or if you learn you have cancer and chemotherapy is given before surgery. Even if the biopsy does not show cancer, the clip helps communicate with your doctors in the future that a particular finding has already been biopsied and shown to be benign. This can avoid someone biopsying the same area all over again because they did not know.

The cytologist or pathologist will write up a report about what they saw in the cells or tissue. You may receive a copy of this report. If you don’t, you should ask your doctor for one.

Our ImPatient Science™ video “Understanding Your Biopsy Report can help you understand what your biopsy report says and means.

Sentinel Node Biopsy

The sentinel node (or nodes) is the first place the cancer is likely to spread. A sentinel node biopsy is the standard of care for evaluating lymph nodes. During most breast cancer surgeries, the lymph nodes under the arm are examined to determine if the cancer has spread beyond the breast. If the chance of finding cancer in the lymph nodes is extremely low—for example, when a woman has ductal carcinoma in situ (DCIS) or a very small tumor—will a surgeon suggest that evaluation of the lymph nodes may not be necessary. In addition, if the information obtained from the sentinel node biopsy will not affect adjuvant treatment decisions, the surgeon may also suggest not performing the procedure.

A sentinel node biopsy is appropriate if:

  • the tumor is in only one location,
  • the tumor is less than 5five cm in size,
  • you have not had previous chemotherapy or radiation therapy,
  • there is no large resection in the upper outer quadrant (more than 6 cm), and
  • there are no palpable lymph nodes (nodes that can be felt with the fingertips).

The surgeon cannot perform a sentinel node biopsy on a woman who has had a breast reduction, has silicone implants, or has two or more lumps in different places in her breast.

If your doctor thinks that the lymph nodes are worrisome, she may suggest an ultrasound prior to the surgery and biopsy the nodes.

The sentinel node biopsy is done at the time of the breast surgery. To identify the sentinel node, some surgeons use blue dye either alone or together with a radioactive tracer. The tracer is usually injected two hours before surgery or up to the afternoon before for early morning surgery. The blue dye is usually injected in the operating room, following the anesthesia. These blue dyes can turn the breast blue, and it can take several weeks to months for the color to fade completely. The dye can also make urine blue and stool can take on a greenish hue.

The radioactive tracer allows the surgeon to wave a hand-held gamma detection probe in concentric circles over the breast to trace the lymph vessels and identify where the sentinel node is most likely to be. Usually, the drainage is to the armpit and a short incision is made just below the hairline over the area with the strongest signal. Next, the tissue is carefully dissected. The surgeon looks for the blue dye in the lymphatic vessel, which will lead to the blue sentinel node or nodes. All the nodes that are radioactive and/or blue (usually two to four) are then removed and sent to pathology for examination.

It is common for your nodes to be evaluated while the surgeon is working on your breast. If the nodes are negative the incision is sewn closed without a drain. If the sentinel lymph nodes are found to be “positive”—to contain cancer cells— then a full axillary node dissection (examination of all the nodes under the arm) can be done at the end of the surgery.

The full dissection may not be done if there is only micrometastases (a small number of cancer cells) found in the sentinel nodes. If the nodes are not evaluated at the time of surgery, and a positive node is found, you may be advised to have additional nodes removed in a full axillary node dissection.

Lymph node dissection can result in a variety of new and often unpleasant sensations in the area of the surgery that may last for some time. Studies have found that tenderness can remain after five years in about 33% of women who had a sentinel node biopsy and in about 40% of women who have a full dissection. Lymphedema is another concern. The risk of developing this painful arm swelling ranges from three to five percent after a sentinel node biopsy compared to 15-20% after full axillary dissection.

If cancer is found in the nodes, it will help guide decisions related to the chemotherapy that is recommended after surgery. Also, removing nodes that contain cancer can help prevent a breast cancer recurrence in the armpit. There is no evidence, however, that removing and examining lymph nodes affects survival.

More Information:

Frequently Asked Questions

Microcalcifications were seen on my mammogram. Should I have a biopsy?

On a mammogram, tiny specks of calcium that look like pieces of dust may show up on the film. Microcalcifications, as we call these specks, are usually the result of normal wear and tear on your breasts, but it is estimated that 20% of the time they’re an indication of cancer or of ductal carcinoma in situ (DCIS). If the film shows only a few very tiny specks arranged in tight clusters, then it’s more likely that there is a problem. If the specks are scattered and larger in size, they’re more likely to be benign and harmless.

When radiologists see microcalcifications on a mammogram, they categorize them as “benign,” “suspicious for cancer,” or “can’t tell.” The benign ones can be left alone, the suspicious ones need to be biopsied, and the “can’t tell” ones can be followed to see how they look on the next mammogram or biopsied. If the radiologist isn’t sure but thinks a microcalcification is benign, you will probably be asked to come back in six months for another mammogram. If, on the other hand, they have any worries, they will recommend that you have a biopsy.

A mass was seen on my mammogram. What happens next?

If a radiologist finds a mass on your mammogram, it has to be evaluated to see what it is. An ultrasound will often distinguish between a cyst or fibroadenoma and a cancer. When mammograms show something round and smooth, it’s likely to be a cyst or a fibroadenoma. If there are jagged, distinct, radiating strands pulling inward, it’s more likely to be cancer. But only a biopsy can confirm that a mass is cancerous.

My doctor says my mammogram and ultrasound show that my breast lump is a series of cysts. Is a biopsy necessary?

If your ultrasound identifies cysts, it makes sense for the radiologist to perform an ultrasound-guided cyst aspiration. If the lump is palpable and proven to be a simple cyst, the clinician could just aspirate it (draw the fluid out), without using ultrasound again.This would be both diagnostic and therapeutic: It would prove that it is a cyst(s), collapse the sacs of fluid and resolve the lump. After the cyst aspirations, another ultrasound could be done to determine whether the lump and cysts are now gone. This might be a good first step rather than having an open biopsy. If a lump does persist, then you could have an open biopsy or have the lump removed.

My pathology result is “fibrofatty tissue.” What does that mean? Is it cancer?

A breast biopsy result of “fibrofatty tissue” means the pathologist saw normal, healthy tissue in your biopsy sample. This means that the lump felt by you or your doctor is really just fatty tissue, and nothing for you to worry about.

My pathology report says I have “atypia.” What does that mean?

In order for the cells removed during a biopsy to be examined, they are put on a slide, stained, and looked at under a microscope. Cells are judged based on a number of criteria, including the size and color of the nucleus (the center of the cell that contains DNA), the appearance of the other structures in the cytoplasm (the area between the nucleus and the outer wall of the cell), and the overall size of the cell itself.

Hyperplasia is the first type of abnormality in appearance. If you receive a diagnosis of hyperplasia it means there are more cells than you would expect to see in the walls of the ducts and lobules, but that all of these cells appear normal. A diagnosis of hyperplasia does not put you at any increased risk for developing breast cancer.

Atypia means that the cells look different from normal cells. You can have atypia with hyperplasia, which means that the cells look different from normal and that there are more cells than you would expect to see. You can also have atypia without having hyperplasia. Atypia does not always progress to pre-cancer (ductal carcinoma in situ DCIS) or cancer. In fact, it is not uncommon for a repeat biopsy in the same area of the breast to show entirely normal-appearing cells. Atypia can be described in a number of ways.

For example:

  • Marked nuclear atypia: The center or the nucleus of the cells looks atypical.
  • Focal atypia: Only a very small area of the total slides inspected had atypia.
  • Atypical ductal hyperplasia: There are extra cells present in the walls of the breast duct and these cells look somewhat abnormal.
  • Atypical lobular hyperplasia: There are extra cells present in the lobules (the parts of the breast that are capable of making milk) and these cells look somewhat abnormal.

A diagnosis of atypia does not mean that you have cancer. Most women with atypia never get breast cancer. A diagnosis of atypia means that you have a “marker” of being at increased risk for developing cancer. The increased risk for a woman with atypia is one percent higher than it is for a woman who does not have atypia. If a woman does not develop breast cancer in 10 years after being diagnosed with atypia, then her risk drops off significantly.

If the atypia was found after you underwent a core biopsy, your doctor will recommend that you have an excisional biopsy, which will remove more tissue. This is done to evaluate the surrounding tissue to make sure that the core did not miss an area that could be cancer. Just as you would get a second opinion from another oncologist, you should get a second opinion from another pathologist. Invasive cancer and benign tissue are both relatively easy to diagnose. But when you are in the atypical hyperplasia to DCIS range there are often very fine distinctions in the degree of hyperplasia and/or degree of atypia, which makes a second opinion a very good idea.

My biopsy report says atypical lobular hyperplasia. What does that mean?

Atypical lobular hyperplasia (ALH) is a term that describes the type of cells that the pathologist saw and where these cells originated.

Hyperplasia is the first type of abnormality in appearance. If a woman receives a diagnosis of hyperplasia it means that there are more cells than normal in the walls of the ducts or lobules, but that all of these cells appear normal. A diagnosis of hyperplasia does not put a woman at increased risk for developing breast cancer.

Atypia means that the cells look different from normal cells, but they don’t have all the features of cancer cells.


Lobular means the cells that are acting unusual are in the lobules, the parts of the breast capable of making milk. The breast ducts are the passages that the milk travels through to get to the nipple. A woman can have atypical ductal hyperplasia or atypical lobular hyperplasia.

A woman can have atypia with hyperplasia, which means that the cells look different from normal and that there are more cells than normal. A woman can also have atypia without having hyperplasia. ALH does not always progress to the pre-cancer lobular carcinoma in situ (LCIS) or cancer. In fact, it is not uncommon for a repeat biopsy in the same area of the breast to show entirely normal-appearing cells.

If the ALH is diagnosed on a core biopsy, the best practice would be to have an excisional biopsy to look at the surrounding tissue to make sure that the ALH is not the tip of the iceberg. If it was diagnosed on the basis of an excisional biopsy, it is important get more details about the size and severity (how different the cells look from normal cells) of what was seen.

The standard treatment for ALH is close follow-up by your doctor, because the presence of ALH increases a woman’s risk for breast cancer in both breasts. But it is important to put this increased risk in perspective. A study by Dr. David Page looked at 252 women with ALH who had been diagnosed on a surgical biopsy. Fifty of them went on to develop invasive cancer; 75% of the time the cancer developed in the same breast in which the ALH was found. In addition, it took, on average, 15 years for the cancer to show up. This tells us that ALH doesn’t progress to cancer rapidly and often never becomes cancer at all. So, yes, ALH does increase risk. But the vast majority of women diagnosed with ALH will never get breast cancer.

In many ways, a diagnosis of ALH is similar to getting an abnormal Pap smear that is not cancerous: both need to be monitored. Monitoring is especially important for women who have a strong family history of breast cancer, and it is recommended these women be seen at a breast care program for high-risk women. These programs provide close follow-up, which means clinical breast exams every six months and yearly mammograms.

Taking tamoxifen for five years for breast cancer risk reduction is an option for women with ALH. You can learn more about the benefits and risk of tamoxifen for breast cancer risk reduction here.

If you have been diagnosed with ALH and have a family history of breast cancer you should make an appointment with a genetic counselor to discuss genetic testing. Women with ALH who carry a BRCA mutation may want to consider a bilateral prophylactic mastectomy (removal of both breasts), which reduces breast cancer risk by about 95%. The surgery is only recommended for women with ALH who have a strong family history of breast cancer. It is not recommended for women solely because they have had an ALH diagnosis.

Micrometastasis was found on my sentinel node biopsy. What does that mean?

Diagnosing micrometastasis can be very difficult. This is because the pathologist needs to determine if what is being looked at are cells that were displaced during surgery or an actual spread of cancer cells. Recent studies have shown that displacement during a sentinel node procedure or an axillary node procedure occurs more often than surgeons originally thought. This displacement of cells is not the same as having metastasis and it does not require treatment with chemotherapy that you would need if it an actual metastasis had occurred.

If only one or several clumps of cells of breast cancer are found in a lymph node based on IHC staining only or RT-PCR only, and they measure less than 0.2 mm, they are considered isolated tumor cells and the nodes are still considered negative. That’s because these are thought to be cells that were dislodged during the sentinel node procedure and not cells that made it to the nodes on their own. Cancer deposits greater than 0.2 millimeters but less than 2 mm are considered micrometastasis and are termed pN1mi, while any that are bigger than 2 mm are considered pN1.

Only an expert in breast pathology can look at the cells and determine if it is truly micrometastasis or if it is cell displacement. For this reason, women who are told they have micrometastasis should always get a second pathology opinion. This second opinion should not come from a general pathologist but from a specialist in breast pathology. To get a second pathology opinion, you will need to have the hospital where you had your surgery performed send your slides to the pathologist you have selected.

You may also want to consider being seen at a multidisciplinary breast care center where you could not only bring your pathology slides and breast films for review, but be seen by a medical team comprised of a  breast specialist, medical oncologist, and radiation oncologist. They would review your pathology slides and mammography images and then discuss as a group how they think you should proceed. To find this type of program in your area, contact the university-based hospital nearest you, the American Cancer Society, a local breast cancer support group, or an NCI Comprehensive Cancer Center.

What is a stereotactic biopsy?

During a stereotactic biopsy the radiologist uses a computer-operated device to guide the needle into the area of interest identified on your ultrasound or mammogram. The needle is large and hollow, and removes a core of tissue. During this procedure, the patient lies face down on an examining table with a hole for the breast to hang through. If mammography is used, an X-ray machine and a maneuverable needle are set up beneath the table. The breast is then x-rayed from two different angles and a computer indicates the exact position of the suspicious mass. The tissue that is removed is then sent to a pathologist. Most women say that the procedure doesn’t hurt. (The only time it tends to hurt is when the radiologist accidentally hits a blood vessel.)

After the procedure is completed, a band-aid is placed over the area in which the needle was inserted, and an ice bag is placed on your breast to reduce pain and swelling. The whole procedure typically takes about one hour. Most of this time involves ensuring the needle is inserted into the proper place.

Can having a biopsy cause the cancer to spread?

If a clinical breast exam identifies a lump, calcifications that look suspicious are seen on a mammogram, or an ultrasound or MRI identifies an area that looks abnormal, a biopsy allows the doctor to determine if the lump or suspicious area is benign (not cancer) or cancer.

A biopsy provides important information. With some types of tumors, such as tumors of the ovary or pancreas, it is possible for a needle to carry a malignant cell to another area. But this is not a concern in breast cancer. Breast cancer cells do not seem to be able to live independently unless they are biochemically ready to do so. This means that the biopsy procedure will not spread the cancer to other areas.

In the future, surgeons will probably have ways to identify whether cancer is present without doing a biopsy. Right now, though, the only way to determine if cancer is present is by doing a biopsy of the lump or microcalcifications, or completely removing the lump, and examining the cells under a microscope.

Love Research Army

We combat the disparities that exist in research by challenging the scientific community to launch studies that are as inclusive and diverse as the people that breast cancer affects.

En Español »