Which ultrasound feature is NOT typically seen with breast cancer?

• A. Taller-than-wide orientation
• B. Shadowing
• C. Irregular contour with spiculated margins
• D. Well-circumscribed, round mass with smooth margins

Answer: (D)

Malignant breast lesions on ultrasound typically show signs of invasive growth: irregular or spiculated margins, a taller-than-wide orientation that reflects growth across tissue planes, and posterior acoustic shadowing from desmoplastic reaction and tissue invasion. These features indicate the lesion is invading surrounding breast tissue, which is characteristic of cancer.

A well-circumscribed, round mass with smooth margins, by contrast, suggests a benign process such as a fibroadenoma or a simple cyst. It grows in a pushing manner with clear borders rather than infiltrating surrounding tissue, which is why this appearance is not typical of cancer.

So the feature not typically seen with breast cancer is a well-circumscribed, round mass with smooth margins.