Which of the following is a characteristic of a simple cyst on ultrasound?

A simple cyst on ultrasound is typically characterized by an anechoic appearance, meaning it appears as a dark area on the ultrasound image with no internal echoes. This anechoic feature is due to the fluid-filled nature of the cyst, which does not reflect ultrasound waves. Additionally, simple cysts have smooth, regular walls that are thin and well-defined, which assists in differentiating them from more complex structures or cysts that may indicate pathology.

The smooth walls of a simple cyst provide a clear boundary, distinguishing it from irregular or thickened walls that may suggest infection or malignancy. This specific combination of being anechoic and having smooth walls is essential in diagnosing a simple cyst accurately. Understanding these characteristics helps sonographers and clinicians identify and assess the nature of cystic structures in the body.