What is the appearance of a mature abscess on ultrasound?

• A. Well encapsulated border
• B. Poorly defined border
• C. Spiculated margins
• D. Shadowing from calcifications

Answer: (A)

A mature breast abscess forms a localized fluid collection that is surrounded by a distinct wall, creating a well-defined border on ultrasound. The organized inflammatory response causes the cavity to develop a capsule, which makes the edges of the abscess stand out clearly against the surrounding tissue. Inside, you may see debris or septations and posterior acoustic enhancement due to the fluid content. Color Doppler often shows peripheral hyperemia around the capsule but not within the cavity. This combination—fluid with a well-defined capsule—is why a well encapsulated border best fits a mature abscess, whereas ill-defined borders, spiculated margins, or shadowing from calcifications point to other processes.