Diagnosis of Hepatic Angiomyolipoma by Combination of Baseline and Contrast-Enhanced Ultrasound—A Prospective Study in Non-Cirrhotic Patients

OBJECTIVES: Hepatic angiomyolipoma (HAML) is a rare, benign mesenchymal tumor of the liver and its diagnosis has been considered challenging. The aim of this study was to investigate prospectively the diagnostic efficacy of the incorporation of both baseline ultrasound (US) and contrast-enhanced ultrasound (CEUS) features of HAML in patients without cirrhosis. MATERIALS AND METHODS: Consecutive 1748 non-cirrhotic patients with focal liver lesions (FLLs) were prospectively enrolled. Baseline US and CEUS were performed before resection or biopsy. Ultrasound imaging diagnosis of FLLs was compared with the pathological results. RESULTS: Final diagnoses were established in 41 patients with HAML (2.3%) with normal alpha fetal protein (AFP) level and in 1707 patients with FLL other than HAML. Diagnostic criteria for HAML was based on the combination of baseline US and CEUS appearance of the nodule: (1) Well-defined, marked hyper-echoic nodule without surrounding hypo-echoic halo on baseline US; (2) hyper-enhancement in the arterial phase (exclude initial peripheral nodular enhancement and spoke-wheel arteries) and remains hyper-enhancement or iso-enhancement in the late phase. The diagnostic criteria were fulfilled in 31 HAMLs, 1 hepatocellular adenoma and 1 hemangioma. Ten HAMLs were misdiagnosed as other liver tumors because they did not meet the diagnostic criteria mentioned above and consequently yielded a sensitivity, specificity, positive predictive values, negative predictive values and Youden index of 75.61%, 99.88%, 93.94%, 99.42%, and 0.75 respectively. CONCLUSION: The combination of baseline US and CEUS may lead to the correct diagnosis noninvasively in the majority of HAMLs in non-cirrhotic patients with normal AFP level.