Which ultrasound feature is commonly associated with malignant breast masses?

• A. Taller-than-wide orientation
• B. Shadowing
• C. Irregular contour with spiculated margins
• D. Marked posterior enhancement

Answer: (C)

In breast ultrasound, how a lesion grows tells you a lot about its nature. Malignant masses tend to invade surrounding tissue rather than stay well contained, which shows up as an irregular, noncircumscribed shape with delicate radiating strands extending from the edge. Those spiculated margins are a hallmark of cancer because they reflect invasive growth and a desmoplastic reaction in the surrounding tissue. This pattern—an irregular contour with spiculations—is more specific for malignancy than other signs.

Other features can appear in both benign and malignant conditions. A taller-than-wide shape can raise suspicion, but it isn’t as specific as spiculated margins. Posterior shadowing often accompanies infiltrative tumors but can also be seen with various benign or fibrotic changes, so it’s less definitive. Posterior enhancement tends to point toward fluid-filled, benign lesions like simple cysts rather than malignancy. So the strongest, most characteristic indicator among these is the irregular contour with spiculated margins.