BACKGROUND: Hepatic angiomyolipoma (HAML) is a rare tumor containing a variable amount of fat, vessels and smooth muscle. We report the image findings on ultrasonography and computed tomography (CT) of huge HAML.
METHOD: The clinical, imaging and pathological data of a case of HAML were retrospectively collected and analyzed.
RESULTS: A huge heterogeneous hyperecho mass with anecho and hypoecho areas inside was found in the left hepatic lobe on ultrasonography. Color Doppler showed blood flow and arterial spectrum in it. CT scan showed a huge heterogeneous solid mass in the left lobe of the liver, with a low density and hypervascular area in arterial phase. The serum tumor marks were all negative. Ultrasound-guided biopsy was taken twice before resection and both showed necrosis tissue and reaction of inflammatory cells. Postoperative pathological results showed that the tumor was composed of epithelioid smooth muscle cells, thick-walled blood vessels and a few adipose cells with necrosis. The immunohistochemistry results showed appearance of typical HAML, with HMB-45 positive and alpha fetoprotein (AFP) negative.    
CONCLUSIONS: Preoperative diagnosis of HAML relies on combination of CT, MRI and ultrasonography. Our case of HAML showed heterogeneous hyperecho image on ultrasonography. Ultrasound-guided biopsy combined with morphological manifestation and specimen examination for HMB-45 may be helpful in the diagnosis of HAML.