What is the most common benign liver tumor and how does it present sonographically?

• A. Cavernous hemangioma: homogeneous, hyperechoic, round, focal, smaller than 3 cm
• B. Focal nodular hyperplasia: Isoechoic, solid, smaller than 5 cm
• C. Hepatic adenoma: Heterogeneous, hypoechoic, poorly defined
• D. Simple hepatic cyst: Anechoic with posterior enhancement

Answer: (A)

Cavernous hemangioma is the most common benign liver tumor. On ultrasound it typically appears as a well-defined, homogeneous, hyperechoic lesion that is round or oval and focal, often smaller than 3 cm. The bright appearance comes from the numerous vascular spaces within the lesion, which reflect sound waves well. Doppler usually shows little or no internal flow, reflecting its vascular but low-flow nature. Larger hemangiomas can be more variable in texture, but the classic grayscale finding is a bright, well-circumscribed nodule. For comparison, simple cysts are anechoic with posterior enhancement and no solid tissue; focal nodular hyperplasia often appears iso- to hypoechoic with a central scar on other imaging, and hepatic adenoma can be more heterogeneous and vascular.