What is the ultrasound appearance of a renal angiomyolipoma?

• A. Hyperechoic, homogeneous, focal, non-vascular.
• B. Hypoechoic, irregular, with vascular flow.
• C. Anechoic and completely cystic.
• D. Mixed echogenic mass with calcifications.

Answer: (A)

Renal angiomyolipoma is best recognized on ultrasound by its fat-rich composition. The fat content makes the lesion highly reflective, giving a bright appearance (hyperechoic) compared with the surrounding kidney parenchyma. The lesion is usually uniform in texture (homogeneous) because fat predominates, and it tends to be a discrete, clearly defined mass within the kidney (focal). On color Doppler, these tumors commonly show little or no internal blood flow, described as non-vascular, helping distinguish them from vascular, malignant masses. Therefore the combination of hyperechoic, homogeneous, focal, and non-vascular aligns with the typical ultrasound appearance of a renal angiomyolipoma.