Understanding Breast Calcifications

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Calcifications are small deposits of calcium that show up on mammograms as bright white specks or dots on the soft tissue background of the breasts. The calcium readily absorbs the X-rays from mammograms. Calcifications typically don't show up on ultrasounds, and they never show up on breast MRIs. Calcifications are a frequent finding on mammograms, and they are especially common after menopause.

Calcifications aren’t connected to the calcium in your diet. They also can’t develop into breast cancer. Rather, they are a “marker” for some underlying process that is occurring in the breast tissue. In most cases, the process is benign (not associated with cancer). As people age, for example, there are more opportunities for benign cell changes that can lead to calcifications. Sometimes the glandular cells of the breast can secrete calcium onto the ducts — after all, the job of the breasts is to make milk, even if you’ve never had children. Other benign processes that can lead to calcifications on mammograms include:

  • past injuries to or infections in the breast
  • benign growths in the breast, such as fibroadenomas, a common type of benign breast tumor
  • breast cysts (fluid-filled sacs)
  • past radiation therapy to the breast
  • calcium buildup in the blood vessels inside the breast (this is the same process that causes calcium to build up in blood vessels throughout the body, a condition called atherosclerosis; often the person will already have cardiovascular risk factors)

Sometimes, though, calcifications can be a marker of underlying cancer development. They may be associated with the presence of ductal carcinoma in situ (DCIS), an early-stage cancer that remains inside the duct, or even invasive ductal carcinoma (IDC) that has spread to the surrounding breast tissues.

When abnormal cells grow unchecked inside the duct, the cells may get so crowded that some of them die and the body can’t clear them away. If this happens, those cells can harden (or petrify) and areas of calcium form. When these calcifications show up on a mammogram, they often have suspicious features that require further investigation.

If you have calcifications as a new finding on your mammogram, the radiologist reading your images has to figure out whether they have any features suggestive of an underlying cancer. If so, additional testing is needed. Still, there is a good chance that the calcifications will turn out to be the result of a benign process. Being called back for additional tests can be nerve-wracking, but try not to jump to conclusions until testing is complete.

Features of calcifications: suspicious or not?

Certain features of calcifications can help your doctor judge whether they are resulting from a process that is: (1) benign, (2) likely benign, or (3) possibly cancer. These classifications have to do with size, appearance, and how the calcifications are distributed in the breast.

Generally, calcifications are more likely to signal a benign process if they:

  • are larger than 0.5 millimeters (mm)
  • have well-defined edges and fairly standard shapes
  • are not clustered in one area of the breast

They are more likely to be associated with a cancerous process if they:

  • are smaller than 0.5 mm each
  • vary in size and shape
  • are clustered in one area of the breast

If calcifications are suspicious, further tests are needed.

NOTE: If calcifications clearly are located in the skin rather than in the breast tissue itself, no further testing is required. It might be necessary to take additional mammography views to confirm this is the case. Sometimes, powder or deodorant residue on the skin can show up as calcifications. Also, if the calcifications are clearly inside the blood vessels of the breast, there is no need for more testing.

Size: larger is less suspicious

Based on their size, calcifications typically are classified as either:

  • Macrocalcifications: These are larger (greater than 0.5 mm), typically well-defined calcifications that often appear as lines or dots on a mammogram. In almost every case, they are noncancerous and no further testing is needed. They become more common as women get older, especially after age 50.
  • Microcalcifications: These are smaller “flecks” (less than 0.5 mm) that resemble small grains of salt. They too are usually not the sign of a problem, although additional features such as appearance and distribution may warrant further investigation.

Sometimes there can be a mix of macro- and microcalcifications.

Appearance: standard sizes and shapes are less suspicious

If the calcifications have a standard appearance, meaning they don’t vary greatly in size and shape, they are more likely to be a marker of a benign process. For example, macrocalcifications appearing as well-defined spheres with transparent centers are common in women over 50. They are usually a sign of benign conditions such as fat necrosis (dead fat cells) or a calcified cyst (a cyst that has hardened).

Large, coarse, “popcorn-like” macrocalcifications can be associated with a benign breast tumor called fibroadenoma.

Smooth, rod-like (linear) calcifications filling individual ducts, often in both breasts, can be a sign of mammary duct ectasia, which occurs when the ducts that lead to the nipple get enlarged and fill with fluid. Calcifications with fat necrosis can happen as a result of surgery or radiation to the chest area.

Microcalcifications that vary in size and shape are of more concern — you may hear these referred to as “pleomorphic calcifications” — and they may be clustered in a specific area of the breast. These can sometimes signal the presence of ductal carcinoma in situ (DCIS), with or without an invasive breast cancer present as well.

Distribution and number: clustered arrangements are more suspicious

If calcifications are clustered together or concentrated in one segment of the breast, they tend to be viewed with more concern. They might appear to be developing within a specific system of ducts or collecting in one segment of the breast. They are less concerning if they are scattered throughout an entire breast or even both breasts.

Some radiologists consider five or more calcifications in a cluster to be possibly suspicious of an underlying cancer. However, this is not a definite cutoff number — others recommend additional testing even if there are fewer than five in a cluster. Again, although microcalcifications are more suspicious, clustered macrocalcifications — or a mix of micro- and macrocalcifications — would also need to be checked out.

There are no hard-and-fast rules when it comes to distribution and number, appearance, and size. You and your doctor will make a judgment based on the mammography images and the radiology report.

Assessment and follow-up testing for calcifications

If calcifications appear on your mammogram, the radiologist will compare your results to your previous mammograms to determine if this is a new finding — or, if you’ve had calcifications before, whether they have changed in number or size. He or she may suggest testing with magnification mammography, which can provide more information about the features of individual particles and clusters. This specialized mammography technique provides more focused views of a specific area of the breast. It may also involve spot compression, which uses small paddles to flatten the area of the breast that is of concern, which can allow for better views.

Depending on your screening facility, you could have magnification mammography right away. However, it’s more likely that you would be called back after the radiologist reads your first mammogram. The call-back mammogram is referred to as a diagnostic mammogram.

The radiologist will characterize the calcifications as:

  • Clearly benign: no further testing is needed
  • Likely benign: you may be asked to come back in 6 months for another mammogram to check on any changes in the features of the calcifications
  • Somewhat or very suspicious: you’ll need additional testing

In most cases, your doctor will order a core needle biopsy, which removes a small piece of tissue in the area to check for underlying cancer. The surgeon or radiologist often has to use mammography to guide a needle to the location of the calcifications, since they are too small to be felt. This is called stereotactic needle biopsy. Your breast would be numbed first with local anesthesia to minimize any discomfort.

In select cases, your doctor might examine the area first using ultrasound or MRI. Even though calcifications typically don’t show up on these imaging tests, the tests can pick up any tissue changes that might be suggestive of cancer. This could help provide further guidance for the biopsy.

You may be anxious about having a biopsy, but the odds are in your favor. Most biopsies for calcifications find that a benign process is the cause. Your doctor may recommend that you come back in 6 months for another mammogram to check for any changes in the calcifications. Or, he or she may recommend that you resume annual screenings. These recommendations can depend on the specifics of the biopsy result, your individual situation, and whether you have risk factors for breast cancer.

If the biopsy finds any abnormal-looking cells (atypia), your doctor may perform a surgical biopsy. This takes a larger piece of tissue to make sure that nothing has been missed. If breast cancer is found, then it would be treated based on your diagnosis.

If you’re ever uncertain about what’s recommended for you after calcifications are found, ask for more information from your doctor or the radiologist who analyzed your images. You may wish to get a second opinion from another radiologist and/or a breast specialist who treats benign breast conditions and breast cancer.

Calcifications after breast cancer treatment and in high-risk women

If you’ve already had breast cancer or you’re at higher-than-average risk due to a strong family history or a genetic mutation, you may be even more concerned about having calcifications on your mammogram. Even in these cases, most calcifications are markers of a benign process. Cancer treatments such as surgery, reconstruction, and radiation therapy can cause tissue damage and scarring, which can lead to calcifications showing up on a mammogram.

Given your situation, though, your doctor should investigate any calcifications thoroughly. You may be more likely to have the area biopsied than a woman who is considered to be at average risk of breast cancer. Also, your doctor may recommend screening with breast MRI in addition to mammography. Your risk factors should be taken into account as you make decisions about further testing and biopsy.


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