ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

Which characteristic may indicate a malignancy in an ultrasound scan?

1. Homogeneous echogenicity

2. Irregular borders of a mass

3. Uniform size of a structure

4. Consistent echogenicity

The correct answer is: Irregular borders of a mass

The presence of irregular borders of a mass on an ultrasound scan is a significant indicator that may suggest malignancy. Unlike benign masses, which typically present with well-defined, regular borders, malignant tumors often exhibit irregular, spiculated, or poorly-defined edges. This irregularity can be indicative of invasive growth patterns where cancerous cells invade surrounding tissues, which differentiates malignant lesions from benign ones that tend to be more contained. In contrast, characteristics such as homogeneous echogenicity, uniform size of a structure, and consistent echogenicity are more commonly associated with benign lesions. These features generally suggest stability and a lack of aggressive behavior, further distinguishing them from malignancies, which are characterized by chaotic growth and a tendency to infiltrate surrounding tissues. Understanding these ultrasound characteristics is crucial for diagnosing and determining the nature of a mass accurately.