An abnormal breast ultrasound usually shows a spot whose shape, edges and darkness differ from the even pattern of normal breast tissue. Most of those spots are not cancer, and many are simple fluid-filled cysts. Radiologists treat what they see as a set of clues, weighing how several features fit together before deciding how suspicious a spot is. The report then ends in a number that predicts what happens next, anywhere from “come back in a year” to “let’s take a sample.”
Shape, Edges and Direction, The Features That Matter Most
A typical cancer looks irregular in shape, with angular, fuzzy edges, and it is taller than it is wide.1The Radiology Assistant. Ultrasound of the Breast It often has a bright rim around it and casts a dark shadow behind it.2The Radiology Assistant. Ultrasound of the Breast A typical fibroadenoma, a common harmless lump, looks quite different. It is oval and sharply outlined, lies flat along the skin, and has a brighter area behind it.3The Radiology Assistant. Ultrasound of the Breast
Reports call a smooth, sharp edge “circumscribed” and describe anything else as “not circumscribed.” Among spots with smooth, regular edges, about 98 in 100 turned out benign.4Radiol Bras. Breast ultrasound: evaluation of echographic criteria for differentiation of breast lesions Among spots with irregular edges, about 7 in 10 were cancer.5Radiol Bras. Breast ultrasound: evaluation of echographic criteria for differentiation of breast lesions A thin bright capsule around a solid lump is also one of the strongest signs that it is benign.6PubMed. Analysis of sonographic features in the differentiation of fibroadenoma and invasive ductal carcinoma
The words on your report for shape are fairly simple. “Oval” or “round” describe simple shapes that lean benign. “Irregular” means the spot is neither, and it raises concern. “Microlobulated,” “angular,” “indistinct” and “spiculated” edges all count as not circumscribed. One worrying word alone does not mean cancer; the overall picture sets the category.
Direction matters too. Benign lumps usually grow sideways along the tissue planes, which reports call “parallel orientation,” or in plain terms, wider than tall. Cancers more often tilt or grow up toward the skin, which reports call “not parallel” or “taller than wide.”7PubMed Central. The utility of quantifying the orientation of breast masses in ultrasound imaging Judging the tilt by eye is less reliable than measuring the angle.8PubMed Central. Quantitative outperforms visual assessment of nonparallel orientation in ultrasound breast imaging reporting and data system9PubMed Central. The utility of quantifying the orientation of breast masses in ultrasound imaging
Dark, Bright and Shadowed Spots
Ultrasound shows breast tissue in shades of gray, and reports rate a spot’s darkness against the fatty layer under the skin.10PubMed. Mixed and Purely Hyperechoic Breast Masses: A Radiologic-Pathologic Review “Hypoechoic” means darker than fat, “hyperechoic” means brighter, and “isoechoic” means about the same. Many cancers are darker than fat, but plenty of benign lumps are too. Shade alone helped little in telling a fibroadenoma from cancer.11PubMed. Analysis of sonographic features in the differentiation of fibroadenoma and invasive ductal carcinoma
Bright spots are usually reassuring. Most are benign, especially evenly bright ones.12PubMed. Mixed and Purely Hyperechoic Breast Masses: A Radiologic-Pathologic Review They are often fat, scar tissue, old blood or healed bruising.13PubMed. Hyperechoic lesions of the breast: radiologic-histopathologic correlation Brightness does not rule out cancer, though, particularly a dark center with a bright rim.14PubMed. Mixed and Purely Hyperechoic Breast Masses: A Radiologic-Pathologic Review
Shadows are the third clue. A shadow is a dark band behind the spot where sound did not pass through.15The Radiology Assistant. Ultrasound of the Breast It is most often linked to cancer, but benign spots such as scars can also cast shadows.16PubMed. Posterior acoustic shadowing in benign breast lesions: sonographic-pathologic correlation A brighter area behind the spot, called enhancement, is typical of cysts and fibroadenomas.17The Radiology Assistant. Ultrasound of the Breast
Other Clues, Calcium, Blood Flow and Nearby Tissue
Radiologists also look at what surrounds a spot: pulled-in or distorted tissue, widened ducts, thickened or pulled-in skin, and swelling.18UCLA Health. Ultrasound: Associated Features These “associated features” can move a spot to a more suspicious category.19UCLA Health. Ultrasound: Associated Features After surgery and radiation, however, skin thickening and distortion are expected and not by themselves worrying.20PubMed. Sonography of the breast: findings following conservative surgery and irradiation for early carcinoma
A color Doppler scan shows blood flow as red and blue on the screen.21Ultrasonography. Up-to-date Doppler techniques for breast tumor vascularity: superb microvascular imaging and contrast-enhanced ultrasound Lots of blood flow, flow in the center, and vessels that branch into the spot suggest cancer. Benign and malignant lumps overlap a lot in blood flow, though.22Ultrasonography. Up-to-date Doppler techniques for breast tumor vascularity: superb microvascular imaging and contrast-enhanced ultrasound
Tiny calcium specks are mainly found on mammograms and are hard to see on ultrasound.23PubMed. Sonographic detection and sonographically guided biopsy of breast microcalcifications When they are visible on ultrasound, they are more often cancer: 69% versus 21% for those not seen.24PubMed. Sonographic detection and sonographically guided biopsy of breast microcalcifications Calcium specks inside a mass are an independent warning sign.25PubMed Central. The utility of quantifying the orientation of breast masses in ultrasound imaging
Cysts, Simple, Complicated and Complex
- Simple cyst: completely black, round or oval, with smooth edges and a bright area behind it. It is benign, BI-RADS 2.26PubMed. Cystic Breast Lesions: Diagnostic Approach and US Assessment
- Clustered microcysts: a bunch of tiny black bubbles with no solid part. Benign, BI-RADS 2.27PubMed. Cystic Breast Lesions: Diagnostic Approach and US Assessment
- Complicated cyst: like a simple cyst but with debris that keeps it from being fully black. Probably benign, BI-RADS 3.28PubMed. Cystic Breast Lesions: Diagnostic Approach and US Assessment
- Complex cystic and solid mass: fluid plus solid parts such as a thick wall, thick dividers or a lump inside. Usually BI-RADS 4, with biopsy.29PubMed. Cystic Breast Lesions: Diagnostic Approach and US Assessment
The difference between a complicated cyst and a complex mass is whether the gray inside is thick fluid or truly solid tissue.30PubMed. Complex cystic breast masses in ultrasound examination What happens next depends on the type. A simple cyst needs nothing unless it hurts, in which case it can be drained for comfort. A complicated cyst usually gets a repeat scan in about six months, and some are drained with a needle to confirm they are just fluid. A complex mass is sampled because the solid part needs to be checked.
What Your BI-RADS Number Means
BI-RADS is a standard scoring system that radiologists use to sum up a mammogram, ultrasound or MRI.31ACR. ACR Breast Imaging Reporting & Data System (BI-RADS) Each category is tied to a recommended next step.32PubMed. BI-RADS(®) fifth edition: A summary of changes
- 0: more imaging is needed before a score can be given.
- 1: nothing found; routine screening.
- 2: a definitely benign finding such as a simple cyst; routine screening.33PubMed. Cystic Breast Lesions: Diagnostic Approach and US Assessment
- 3: probably benign; cancer turned up in about 1 in 100.34PubMed. Accuracy of classification of breast ultrasound findings based on criteria used for BI-RADS
- 4: suspicious; about 1 in 6 turned out to be cancer when biopsied.35PubMed. BI-RADS 3, 4, and 5 lesions: value of US in management–follow-up and outcome
- 5: highly suggestive; more than 9 in 10 were cancer.36PubMed. BI-RADS 3, 4, and 5 lesions: value of US in management–follow-up and outcome
Category 3 spots are usually rechecked over 6 to 24 months rather than sampled.37PubMed. BI-RADS 3, 4, and 5 lesions: value of US in management–follow-up and outcome The rare cancers found among them were small and had not spread to lymph nodes.38PubMed. BI-RADS 3, 4, and 5 lesions: value of US in management–follow-up and outcome A spot that grows somewhat without changing shape still stays low risk, about 2%.39PubMed Central. Growing BI-RADS category 3 lesions on follow-up breast ultrasound: malignancy rates and worrisome features
Many reports split category 4 into 4A, 4B or 4C. 4A is low suspicion, 4C is high, and 4B sits in between. All of them lead to a biopsy, but 4A is far more often benign.
Harmless Conditions That Can Look Like Cancer
Irregular dark masses are not always cancer; many benign conditions look the same.40PubMed Central. Are Irregular Hypoechoic Breast Masses on Ultrasound Always Malignancies?: A Pictorial Essay Fat necrosis, which is damaged fat after an injury or surgery, can look like a solid dark mass with a shadow.41PubMed Central. Fat Necrosis of the Breast: A Pictorial Review of the Mammographic, Ultrasound, CT, and MRI Findings with Histopathologic Correlation It changes appearance over time as it heals.42PubMed Central. Fat Necrosis of the Breast: A Pictorial Review of the Mammographic, Ultrasound, CT, and MRI Findings with Histopathologic Correlation Infection or trauma can often be suspected from symptoms and history.43PubMed Central. Are Irregular Hypoechoic Breast Masses on Ultrasound Always Malignancies?: A Pictorial Essay
That is why it helps to tell your doctor about any bruise, seatbelt injury, surgery, biopsy or breastfeeding infection. This history helps the radiologist consider a benign mimic. It may not avoid a biopsy, but it guides the interpretation.
Stiffness Scans and Why Ultrasound Follows a Mammogram
Some centers add elastography, which shows how stiff a spot is.44PubMed. Comparison of shear-wave and strain ultrasound elastography in the differentiation of benign and malignant breast lesions Benign lumps tend to be firmer than normal tissue but softer than cancer,45Ultrasonography. Shear-wave elastography in breast ultrasonography: the state of the art so adding a stiffness scan to standard ultrasound improved accuracy.46PubMed. Comparison of shear-wave and strain ultrasound elastography in the differentiation of benign and malignant breast lesions Reports may describe stiffness as soft, intermediate or hard.47IntechOpen. Breast Ultrasound
Ultrasound often follows a mammogram because mammograms miss more cancers in dense breasts.48PubMed Central. The Role of Ultrasound in Screening Dense Breasts—A Review of the Literature and Practical Solutions for Implementation Ultrasound finds about 3 to 4 extra cancers per 1,000 women with normal mammograms.49PubMed Central. Role of Breast Ultrasound for the Detection and Differentiation of Breast Lesions It also increases callbacks for spots that turn out benign.50PubMed. Automated Three-dimensional Breast US for Screening: Technique, Artifacts, and Lesion Characterization
What Happens at an Ultrasound-Guided Biopsy
The doctor uses the ultrasound image to guide a hollow needle into the spot.51PubMed Central. Ultrasound-guided core-needle biopsy of breast lesions A 14-gauge cutting needle is common, and larger vacuum-assisted needles are increasingly used.52PubMed Central. Ultrasound-guided core-needle biopsy of breast lesions
You lie on your back and the skin is numbed. A small nick lets the needle in, and you hear a click as samples are taken. A tiny marker clip may be left to mark the spot. Expect bruising and soreness for a few days.
Results usually come in several days. The doctor checks whether the tissue fits the images, and a mismatch may lead to a repeat or surgical biopsy.
Abnormal Findings in Men and Women With Implants
Breast enlargement in men, called gynecomastia, sits centered behind the nipple, while cancer usually sits off to one side.53The Radiology Assistant. Pathology of the Male Breast The two can overlap, so mammogram and ultrasound are often used together.54PubMed. Male breast carcinoma and gynecomastia: comparison of mammography with sonography A hard, painless, off-center lump needs prompt evaluation. Tender swelling on both sides more often points to gynecomastia, which medicines and hormones can cause, but it still deserves a doctor’s check.
With implants, leaked silicone looks like a bright “snowstorm” that hides everything behind it.55PubMed. Silicone implant rupture: detection with US Multiple broken parallel lines inside the implant suggest rupture.56PubMed. Sonographic signs of breast implant rupture Ultrasound can also spot silicone that has reached lymph nodes in the armpit.57PubMed. Silicone implant rupture: detection with US