Ultrasound Differentiation of Lipoma and Hemangioma

Characteristic Ultrasound Features

Lipomas appear hyperechoic or isoechoic compared to surrounding fat, with well-circumscribed margins, and display thin, curved echogenic lines within an encapsulated mass, showing minimal to no internal vascularity on Doppler examination, and demonstrate no acoustic shadowing, according to the American College of Radiology 1, 2, 3
Hemangiomas demonstrate increased internal vascularity on Doppler examination, which is the key distinguishing feature from lipomas, and may show phleboliths on plain radiographs, as recommended by the American College of Radiology 1, 4

Ultrasound achieves high diagnostic accuracy for superficial soft tissue masses, with sensitivity of 86.87-94.1% and specificity of 95.95-99.7%, as stated by the American College of Radiology, with the highest accuracy for lipomas among all superficial soft tissue masses 1, 2

The American College of Radiology recommends beginning with plain radiographs as the fundamental first step, which can identify phleboliths within hemangiomas or intrinsic fat in lipomas, then proceeding to ultrasound for further characterization, particularly for superficial or palpable masses, and using Doppler examination to assess vascularity 1, 2, 4
Small, superficial, asymptomatic masses with typical lipoma features can be observed clinically, as suggested by the American College of Radiology, and when ultrasound features are typical for either lipoma or hemangioma, further imaging may not be necessary 2, 3

The American College of Radiology advises that atypical ultrasound features, including heterogeneous echotexture, irregular margins, or unexpected vascularity patterns, size >5 cm in diameter, deep-seated location, rapid growth, pain, or tenderness, and lower limb location, require advanced imaging, such as MRI, which is the preferred modality when ultrasound is indeterminate or shows concerning features 2, 4