Breast Ultrasound Practice Test

The key idea is how a lesion sits in the breast tissue on ultrasound. Benign lesions like fibroadenomas tend to grow along the natural tissue planes, so their long axis runs more horizontally in the transverse view. This gives a wider-than-tall orientation, meaning width exceeds height on the image. This parallel growth to the skin and surrounding tissue is a reassuring, classic feature of fibroadenomas.

In contrast, a taller-than-wide orientation suggests the mass is expanding more in the vertical dimension, often because it invades across tissue planes, which raises concern for malignancy. While shape and margins matter, the orientation described as wider-than-tall is the characteristic sign for a benign fibroadenoma.

Rounded shapes with smooth, well-defined margins fit the typical benign pattern, whereas spiculated or irregular margins point more toward malignancy. So the imaging orientation that best characterizes a fibroadenoma is wider-than-tall.