Mammogram Findings and Breast abnormalities
There are about eight typical kinds of abnormalities that a conventional or diagnostic mammography may show.
An experienced radiologist is highly tuned to the appearance of breast abnormalities in diagnostic imaging. This is why, most of the time, the radiologist has a pretty good idea whether a suspicious abnormality is likely to be malignant or not.
Typical mammogram findings from breast cancer screening
- Asymmetric Breast Tissue
- Asymmetric Density
- Architectural Distortion Mass
- Interval Changes in comparison to previous films
- Other Miscellaneous Findings
Abnormal Mammogram Findings: The Next Step
Usually, abnormal mammogram findings will require some form of call-back or follow-up.
Follow up usually involves additional imaging studies, such as breast ultrasound or breast MRI. However, if the lesion still appears suspicious, a breast biopsy may be necessary.
Just a heads up, we have a brand new page with up to date information on abnormal mammograms.
Asymmetrical breast tissue
Asymmetrical breast tissue is in respect to the same area on the opposite breast. So, basically when the same area of the breasts are compared there is a difference in breast tissue.
But, don’t worry, this is a fairly vague finding in which there is no focal mass, no distorted architecture, no central density and no associated breast calcifications.
Usually about 3% of breast screening mammograms will show asymmetric breast tissue.
Furthermore, only a very small percentage of women with asymmetrical breast tissue will end up actually having a breast biopsy. Typically, a breast cancer diagnosis will only be given to a very small percentage of women with asymmetrical breast tissue.
An asymmetric density mammogram result is only a concern if there are associations with a clinically palpable abnormality, or a palpable mass. Otherwise, a certain amount of asymmetrical breast tissue is a normal variation that occurs in some women.
In some cases, however, the asymmetrical breast density is Pseudo-Angiomatous Stromal Hyperplasia, but this condition is mostly benign.
An asymmetrical density mammogram in terms of the first mammographic finding usually refers to an ‘opacity‘ (obscured view in part of the breast) which is visible on only one projection (or one ‘view or angle‘ of the X-ray).
Typically, the radiologist will request additional views from other X-ray angles as an immediate follow up.
Asymmetric densities can be the result of other benign causes such as:-
- Post surgical scarring
- A simple cyst
- Sclerosing Adenosis
- Focal fibroglandular tissue growth: that may develop as a result of hormone supplementation
However ductal or lobular breast carcinoma can also cause asymmetric breast tissue density.
In the absence of an actual ‘mass‘, breast cancer is quite unlikely, but follow-up imaging is necessary, so don’t quit having mammograms.
Often, an ultrasound will be the next step, and if ultrasound finds nothing, or finds cysts, that is good news. If ultrasound finds a solid abnormal mass, then a biopsy is necessary.
Mammogram Findings: Asymmetric breasts
And now … for something completely different, nothing to do with cancer. Did you know that it is common for a woman’s breasts to be asymmetrical in a mirror?
Mammogram Findings: Architectural distortion
An architectural distortion on a mammogram is basically a disruption of the normal ‘random‘ pattern of curvilinear and fine linear radiopaque structures normally seen on a breast X-ray.
There is no visible mass, but the distortion often appears as a ‘stellate‘ shape or with radiating speculations.
Patients who have architectural distortion on mammography are more likely to have positive margins than patients with masses or calcifications.
This may be because architectural distortion on mammography is most commonly due to benign conditions, causing the surgeon to excise with minimal margins.
Tumors presenting as architectural distortions on mammography are also significantly larger than tumors presenting with other mammographic abnormalities.
Patients undergoing biopsy for non-palpable architectural distortions will have wider excisions to reduce the risk of positive margins.
Specialists estimate that around 4% of women who undertake a screening mammogram present with an architectural distortion. The number of those women in which the architectural distortion would actually represent invasive breast cancer is very low, perhaps 5%-7% of the 4% with architectural distortion, which becomes a very small number.
lol, you never do math. It’s 0.05 x 0.04 which gives 0.2%
Mammogram Findings: Architectural Distortion and Cancers
Clearly, most architectural distortions on mammography are due to benign causes.
As a result, most biopsies of suspicious architectural distortions tend to be a little bit on the small side. But in the event it did represent invasive breast cancer, it is important to excise the lesion with wider margins.
Architectural distortions often are an accompanying feature of breast cancer masses as well. Almost 80% of breast masses have architectural distortions that turn out to be invasive cancers, such as, invasive lobular carcinoma or invasive ductal carcinoma.
Mammographically detected breast mass
The mammographic image below shows a small nodule with suspicious indistinct margins, possibly invasive ductal carcinoma.
The word nodule is a term specialists use to describe a small mass. The word lump (as in breast lump) refers to something a person feels with their fingers.
Characteristics of mass shape, margin and density, can suggest malignancy
In terms of shape, if it is round, oval or slightly lobular, the mass is probably benign.
But, if the mass has a multi-lobular contour, or an irregular shape, then it is suggestive of malignancy. ‘Margin‘ refer to the characteristics of the borders of the mass image.
When the margin is circumscribed and well-defined the mass is probably benign. If the margin is obscured by more than 75% by adjacent tissue, it is moderately suspicious of malignancy.
Likewise, there is moderate suspicion if the margin is microlobulated ( i.e. having many small lobes ). If the margin is indistinct or spiculated (consisting of many small ‘needle-like‘ sections) then there is also high suspicion of malignancy.
‘Density‘ is usually classified as either fatty, low, iso-dense or high. The mass is probably benign for fatty and low densities, moderately suspicious of malignancy for an iso-density and highly suspicious of malignancy at high densities. The mammographic characteristics of breast masses is quite a complex and detailed study.
Mammogram Findings: Microcalcifications
Microcalcifications are one of the main ways radiologists detect breast cancer on mammogram in the very early stages (Ductal carcinoma in situ (DCIS).
Microcalcifications are actually tiny specks of mineral deposits (such as calcium). They distribute themselves in various ways. Sometimes microcalcifications are found scattered throughout the breast tissue, and they often occur in clusters.
Most of the time, microcalcification deposits are due to benign causes. However, certain features and presentations of microcalcifications are more likely to be associated with malignant breast cancer.
Benign and malignant indicators for microcalcifications
|Morphology||Popcorn egg shell with a dense center||x (adenofibroma)|
|curvilinear egg shell with a clear center||x (calcified cyst,
|intra and peri-ductal bilateral||x (secretory disease)|
|smudgy on CC and fluid level on lateral||x (milk of calcium)|
|crushed stone/BIRADS: pleomorphic, heterogeneous||x|
|segmental/within a major system, wedge shaped, nipple oriented||x|
|clustered/usually grouped in less than 2 cubic centimetres||x|
|linear, branching within the galactophores||x|
|Size and number||size in mm||x ( >1 )||x ( < 0.2 to 1 )|
|number per cubic centimetre||x ( < 3.5 )||x ( > 3-5 )|
When microcalcifications are encountered on a mammogram, knowing that Ductal carcinoma in situ (DCIS) is common, the chances are good that it could be DCIS and less likely to be invasive cancer. It all depends on what the actual microcalcifications look like and how extensive they are, some could appear as ‘suspicious calcifications’.
Mammogram Findings: Types of Microcalcifications
If the microcalcifications are ‘Powderish‘, with either a fine, indescernible, or ‘cotton ball‘ appearance, then the probability of DCIS is about 47% and most frequently results in a ‘low-grade‘ cancer.
When the microcalcifications have the ‘Crushed Stone‘ characteristic, appearing either as coarse, granular, angular, broken-needle-tip, arrowhead, or a spearhead shape, then the probability of DCIS is about 61%. A breast cancer classified as low to intermediate-grade. But if the microcalcifications have a ‘Casting‘ appearance, then the probability of DCIS is about 96%, the breast cancer is classified as high-grade.
Casting microcalcifications typically appear in two variations. Variant A is called ‘dense casting‘, with linear and branched, fragmented or irregular features. Variant B is called ‘dotted casting‘, with granular and branched, dotted or snakeskin-like features.
Note, while DCIS is generally considered a milder breast abnormality, it must be stressed that not all kinds of DCIS with microcalcifications are highly curable.
There is a new line of scientific evidence which identifies a highly aggressive-invasive subtype of casting microcalcification in the micropapillary DCIS subtype, which has a poor prognosis and should be treated with mastectomy.
The relative ratio between the carbonate content and the protein matrix within the microcalcification may also have some relationship to the type of grade of ductal carcinoma associated with them.
Mammogram Findings: A quick Q and A Session
- Why do microcalcifications form? When gunk gets stuck in blocked milk ducts, over time it gets hard and binds calcium.
- How dangerous are microcalcifications? They aren’t the dangerous thing. It’s whatever blocked the ducts. So rephrasing…
- How dangerous is a cancer with a cluster of microcalcifications? The cancer is judged on its own features, and the microcalcifications have no added danger.
- How risky are scattered microcalifications? Not at all.
An ‘interval change‘ is simply a notable difference on a second or third scan in comparison to a previous scan.
Typically there may be changes in size, density and contour of the mass, or changes in size, number, configuration and pattern of microcalcifications. A change in the dense tissue or contour of a mass is a fairly definite sign of malignancy. However, changes in the pattern of microcalcifications is thought to be a less reliable indicator of malignancy.
Interval change might be one area where a computer aided detection system can assist in breast cancer identification, but an experienced radiologist is sure to be suspicious of any interval changes on mammograms. (The ‘screening interval‘ is the recommended amount of time between ongoing breast cancer screenings, usually 1 to 2 years.)
Adenopathy refers to a finding of enlargement of the lymph glands. A very small percentage of women undergoing a breast cancer screening mammogram will present with these features. (In some cases the mammogram detects enlarged axillary lymph nodes, but no breast mass. Sometimes the cause is an ‘occult‘ primary breast cancer, either obscured from view or newly developed in a different region of the breast (or in the opposite breast.)
An axillary lymph node that seems enlarged on a mammogram could contain cancer, but some lymph nodes can be quite large normally.
However, mammographical features of benign and malignant lymphadenopathy are quite often indistinguishable. Sometimes the presence of intranodal calcifications (nodular density), or abnormal lymph nodes on imaging, can be more suggestive of malignancy as well.
As a rule of thumb, an axillary lymph node is suspicious if its size is greater than 2 cm and with no fatty hilum.
More precicely, when a lymph node has a fatty hilum visible, the outer cortex should be 5 millimeters thick at most, but is usually less. When the cortex is 6 mm or thicker, the chances that a cancer has spread into the lymph nodes are significant. If there is no fatty hilum visible, then the entire lymph node measured across its smallest short-axis width, should be no larger than 10 millimeters.
Ultrasound is often useful as a follow-up when enlarged lymph glands are detected. Some of these will be referred for either a fine needle or excisional biopsy. Sometimes a suspected enlarged lymph node turns out to be either a lipoma, fibroadenoma, or a haematoma.
Common Causes of Enlarged Lymph Nodes
Common benign causes of benign lymphadenopathy might also include reactive nodal hyperplasia, or collagen vascular disease. An acute bacterial infection or tuberculosis might also bring about the condition.
If the lymphadenopathy is actually caused by a malignant carcinoma, it is often associated with breast cancer development in the previously unaffected breast.
Other findings of note on a screening mammogram might include a finding of inflammatory breast cancer, or possibly diffuse reticular breast density, and also skin thickening.
We hope that this post will help when you receive any radiology report regarding breast imaging and findings.
Lets do a quick Q & A’s
- What about if ultrasound shows a hypoechoic focus or a breast mass? It’s basically the same issue and the approach to the solution involves similar algorithms to a mammographic mass. Look at the margins, shape and size and decide if it needs a biopsy and later maybe excision or removal.
- How often are there no symptoms? Quite often. And conversely, whether or not a lump is palpable or hurts, it doesn’t really change the statistics or the workup.
- What is an incomplete mammogram result? If you get an ‘incomplete mammogram’ report try not to worry. It means that there is a potential abnormality but it could not be clearly seen and further investigations may be necessary. This happens in a lot of women’s health screening centres and is often a result of having dense breast tissue making a diagnostic mammogram or ultrasound much more difficult to read.
This may also suggest that the mammogram should be compared with older ones to see if there have been changes in the area over time.
- Samardar P, de Paredes ES, Grimes MM, Wilson JD. (2002) Focal asymmetric densities seen at mammography: US and pathologic correlation. Radiographics. 2002 Jan-Feb;22(1):19-33. https://www.ncbi.nlm.nih.gov/pubmed/11796895
- Ayres FJ, Rangayvan RM. (2005) Characterization of architectural distortion in mammograms.Engineering in Medicine and Biology Magazine, (Feb. 2005) Vol 24, 1. p. 59-67. https://www.ncbi.nlm.nih.gov/pubmed/26138756