What is the typical appearance of breast cancer on a mammogram and ultrasound?

Typical Appearance of Breast Cancer on Mammography and Ultrasound

Breast cancer typically presents on mammography as an irregular mass with spiculated or indistinct margins, and on ultrasound as an irregular hypoechoic mass with non-parallel orientation and posterior acoustic shadowing.

Mammographic Features of Breast Cancer

• Breast cancer most commonly presents as an irregular mass with spiculated or indistinct margins on mammography 1
• Approximately 80% of ductal carcinoma in situ (DCIS) presents with suspicious microcalcifications that can be identified regardless of breast density 1
• Microcalcifications associated with high-grade DCIS and DCIS with necrosis typically appear as fine pleomorphic or fine-linear branching calcifications 1
• Low and intermediate-grade DCIS may present with round/punctate calcifications or an asymmetry without calcifications 1
• The shape of clusters of microcalcifications is often irregular or triangular, suggesting a segmental or ductal distribution 1
• Less common mammographic presentations include focal asymmetry, architectural distortion, or a developing density 2
• Some breast cancers may present with a single dilated duct as the only mammographic finding 2
• Malignant calcifications are typically grouped or clustered, pleomorphic, fine, and may show linear branching patterns 3

Ultrasound Features of Breast Cancer

• On ultrasound, breast cancers typically appear as hypoechoic solid masses (95% of cases) with irregular shape (73%) 4
• Malignant masses commonly show spiculated or angular margins (63%), non-parallel orientation (63%), and variable posterior acoustic features 4
• Male breast cancers typically manifest as hypoechoic solid masses with irregular borders on ultrasound 1
• Ultrasound is less sensitive than mammography for detecting DCIS (47% vs 55%) 1
• The typical appearance of suspicious calcifications in isolated DCIS is more commonly assessed as highly suggestive of malignancy with mammography (87%) than with ultrasound (33%) 1
• Posterior acoustic shadowing is a common feature of invasive ductal carcinoma but may be less common in other breast cancer subtypes 5

Differences Between Imaging Modalities

• Mammography has high sensitivity (92-100%) and specificity (90-96%) for breast cancer detection 1
• Ultrasound sensitivity for distinguishing benign from malignant disease ranges from 88.9-100%, with specificity of 74-95.3% 1
• Mammography is more sensitive than ultrasound for detecting DCIS due to better visualization of microcalcifications 1
• Digital breast tomosynthesis (DBT) can address some limitations of standard mammography by decreasing the lesion-masking effect of overlapping normal tissue 1
• MRI has higher sensitivity for detecting high-grade DCIS compared to mammography (92% vs 56%) 1

Important Considerations and Pitfalls

• Dense breast tissue can mask cancers on mammography, reducing sensitivity to as low as 30% 6
• The upper outer quadrant and area under the areola and nipple contain the highest concentration of glandular tissue and are the most common sites for cancer to arise 6
• Women with extremely dense breast tissue have a 4-6 fold greater risk of developing breast cancer compared to those with fatty tissue 6
• Some breast cancer subtypes may present with atypical imaging features - for example, metaplastic carcinomas tend to show more benign imaging features such as round or oval shape with circumscribed margins 5
• Negative imaging evaluation should never overrule a strongly suspicious finding on physical examination; any highly suspicious breast mass detected by imaging or palpation should undergo biopsy 1
• Breast cancer in younger women (<40 years) commonly presents as masses with irregular shape and spiculated margins on mammograms, and irregular shape with microlobulated or angular margins on ultrasound 7