What is a common feature of a simple cyst as seen in ultrasound?

A simple cyst is characterized by its clear and specific ultrasound appearance. It typically appears anechoic, meaning it does not produce echoes on the ultrasound, which indicates that it is filled with fluid. The term "acoustic enhancement" refers to the phenomenon where the sound waves pass through a fluid-filled structure without significant attenuation, resulting in increased echogenicity behind the cyst. This is often visualized as an area of increased brightness beneath the cystic structure.

These features are critical in distinguishing simple cysts from more complex masses. The other characteristics mentioned, such as irregular borders, solid masses, and complex structures with septation, are indicative of non-simple cysts or other types of masses, which could signify potential abnormalities or malignancies.

Thus, the primary attributes of a simple cyst being anechoic with acoustic enhancement help radiologists and sonographers reliably identify these benign structures in breast imaging.