A mammogram ( a combination of X-ray images of the breast ) is a routine part of a breast cancer screening program. 'Breast palpation' programs (physically checking for lumps) are generally agreed to be insufficient. Breast self examination programs are also unreliable, as a lesion can develop for years before it becomes palpable. Of course, when a 'bump' or 'lump' of some kind has been found on a clinical exam by a family physician, the patient will immediately be referred for a mammogram. Women with higher than average risk factors and older women should generally have them performed more frequently.
Normally, the X-ray component of a mammogram is all that is required for breast cancer screening purposes. An ultrasound is typically a 'second look' type of application. It is not a good idea to have an ultrasound and not a mammogram, and it is probably best to follow the advice of the screening physicians.
On a mammogram, a lesion will usually appear as 'brighter' than the surrounding tissue. This is because things that are denser than fat will stop more x-ray photons, hence they appear brighter.
Ultrasounds are a little harder to figure out. The darkest images on a sonograph are cysts containing liquid. Solids are less definitive. With ultrasound the radiologist will probably be trying to get a sense of the internal texture of the suspected breast lesion and surrounding area. Solid lesions can be a little brighter or darker than the surrounding tissue, and the way to evaluate them on ultrasound is to look closely at the margins or the 'outer edges' of the nodule.
The X-ray image below shows a suspected mass of about 1 cm in diameter. Some architectural distortion is also apparent.
An ultrasound image of the same lesion suggest that the lesion is solid. The mass appears to be hypoechoic with ill-defined, spiculated, and microlobulated margins. It is not possible to rule out malignancy here because posterior acoustic shadowing is not present. When a lesion is homogeneous, good 'through-transmission' of the ultrasound beam is possible, and malignant breast cancer lesions are typically not so homogenous.
The X-ray image below shows a lesion with 'asymmetric density'. That indicates that the lesion likely contains a variety of elements, which may or may not indicate breast cancer.
On the sonogram below, the asymmetric density observed in
the X-ray appears to be fat tissue. This is due to the fact that although
its a little darker-appearing on ultrasound than other fat, it has internal
texture resembling a fat lobule.
There is an apparent 'capsule' ,which is the thin bright line around the outside of the dark oval area. (A capsule is a fibrous covering that surrounds some things like lipomas.)This suggests the lesion might be harmtoma or fibroadenolipoma, but as there is no apparent capsule on the X-ray, this is less likely. Usually in a post-traumatic or post-operative hematoma there would be a collection of solid and liquid components, and that does not appear to be the case here.
The site requires further investigation, perhaps by 'spot films' with compression, (which gives a more detailed view of the lesion itself and not the surrounding breast tissue) . Likely diagnosis might be fibroglandular dysplasia or other fibrocystic changes.
The image below contains a lesion with irregular, spiculated margins. There does not appear to be a 'central' mass to this lesion, which right makes it less likely to be breast cancer. However, something this suspicious would likely be biopsied to find out exactly what is going on.
It is more likely to be either a post-surgical scar, or possibly a 'radial scar'. In actual fact this particular image was taken from a woman who had breast surgery, so a post-surgical scar is the most probable diagnosis.
A closer look via magnification of the same lesion reveals a central radio-transparency likely caused by fat necrosis, and there is no central mass. The spiculations around the lesion are likely a 'desmoplastic' reaction to the surgery. ( 'desmoplasia' refers to the growth of fibrous and connective tissues. This is common following surgery, and is often simply referred to as 'scar tissue'. )
Male breast cancer is very rare, but a condition called "gynecomastia", which is the development of abnormally large breasts in men, is quite common. Gynecomastia is usually caused by excessive growth of fibroglandular breast tissue in men in their 60s, or as the result of hormonal imbalances. But, it may be caused by breast cancer as well, so a full mammographic investigation is always warranted.
In the mammogram below, one can see the increased density of the fibroglandular tissues behind the nipple. It appears to be developing in a concentric pattern. The contour of the dense area is 'concave-outward', and interspersed with fat. There are no well-formed masses and no suspicious microcalcifications. It certainly would appear to be gynecomastia from natural or hormonal causes, and not breast cancer.
In the sonogram of the same breast one notes that the density appears hypoechoic, and with ill-defined margins. The "amount" of tissue appears to be thicker than average in a male, but the only way to know if anything abnormal is going on in the sonogram would be to compare it with an ultrasound of the other breast, and see if the densities are about the same.
Breast cancer is very uncommon in younger women. So, if a young woman who was pregnant came in for screening of a palpable lump on her breast, it is far more likely that the lesion is a fibroadenoma of some kind. One common variation of fibroadenoma in pregant women is a 'lactating adenoma', which is essentially a tubular adenoma occuring in pregnant women and thus featuring accumulation of milk secretions in addition to hyperplasia.
Breast X-rays are not normally given to pregnant women. Given that breast cancer is very unlikely and lactating adenoma is quite likely, ultrasound and possibly a fine needle aspiration biopsy would typically be utilized for diagnostic investigations. The main concern with a lactating adenoma from the perspective of breast cancer is that the condition can occur simultaneously with breast carcinoma. However, on their own they are of absolutely no increased risk for subsequent breast cancer development.
In the ultrasound image of lactating adenoma below, one notes a hypoechoic, non-cystic mass in an ovoid shape. It has a long axis running parallel to the skin, posterior acoustic enhancement, and well-defined margins
Mammograms of lactating ademonas (not generally given to pregnant women) will tend to show an oval well-circumscribed mass with radiolucent (somewhat transparent ) central areas. (radiolucent features will appear darker on an X-ray) Ultrasounds of lactating adenomas tend to reveal the heterogenous echotexture of the tumor, with central hyperechogenic areas. The radiolucent (X-ray) and hyperechogenic (ultrasound) areas will indicate the fat content of the milk secretions in the tumor.
Since lactating adenomas occur in pregant and breastfeeding women, this tends to simplify diagnosis. An abscess, for example, would be unlikely in the absence of erytheme (redness often due to inflammation) or skin edema.(a 'bulge' caused by the build up of fluids) Lactating adenomas also tend to be only slightly painful, unlike an absess. But, to exclude any possibility of malignancy a fine needle biopsy is usually performed anyways. Fine needle biopsy is actually preferred over a core biopsy in suspected lactating adenomas, because milk secretions can 'find their own paths' through various tissues and confuse the issue.
In the cytologic image of lactating adenoma below, there are many more ducts than would normally occur ( hyperplasia). The ducts are dilated and contain milk secretions. The proliferation of new ducts distinguishes the lesion from a simple galactocele, which is just an accumulation of milk that cannot escape through normal channels.
Lactating adenomas, like fibroadenomas, are somewhat prone to infarction (tissue death from compromised blood supply), and this can lead to some strange and misleading features, possibly suggestive of malignant breast cancer. Some of these features may include things like structural heteroechogenicity, microlobulated margins, pronounced hypoechogenicity, posterior acoustic shadowing, and irregularly shaped masses. A fine needle aspiration is warranted given any unexpected or unusual element such as this.
It takes years of radiological experience to gain facility in interpreting mammograms. However, anything abnormal, and especially features which show unusual density, odd shapes, and irregular border, will be referred for biopsy. Interpretation accuracy improves over the first three years of practice, and continues to be refined over the course of a radiologist's career. For some reason, the rate of 'abnormal findings' on mammograms is slightly higher in North America than in Europe.
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