Angiomyolipoma mimicking hepatocellular carcinoma on preoperative magnetic resonance image: The way to prevent unnecessary surgery for hepatic angiomyolipoma

Abstract

The magnetic resonance imaging (MRI) of hepatic angiomyolipoma (AML) is often mistaken for hepatocellular carcinoma (HCC). In this study, clinicopathological, and imaging features of hepatic AML misdiagnosed with a malignant tumor before surgery were reviewed. A total of 34 patients diagnosed with hepatic AML by surgery (n = 20) or biopsy (n = 14) were included (2008-2020). Twenty female and fourteen male patients with a mean age of 52.9 years (range 28-78) were followed-up for about 68.23 months. Only one patient was positive for HBsAg among 34 cases, and preoperative levels of serum alpha-fetoprotein and protein induced by vitamin K absence-II were not increased for all patients. Two patients showed non-alcoholic fatty liver disease. Twenty-nine patients have solitary liver tumor and the remainder has multiple ones. In two cases, renal AML was simultaneously diagnosed. In preoperative MRI, AML was misdiagnosed as HCC (n = 14, 41.2%), adenoma (n = 1, 2.9%), cholangiocellular carcinoma (n = 1, 2.9%), intrahepatic metastasis of malignant tumor (n = 2, 5.8%), or inconclusive opinions (n = 6, 17.6%). In subgroup analysis, overall survival was not different (p = 0.496), on the contrary, biopsy group showed significantly short length of hospitalization (p =0.001), small tumor size (23.5 mm versus 45.8 mm, p = 0.017), better diagnostic accuracy (50% versus 15.0%, p =0.011). In immunohistochemical analysis, several antibodies were detected including HMB45 (in 32 cases), SMA (n = 19), CD 34 (n = 7), Melanin A (n = 5). Since AML is a benign tumor, for the suspicious HCC suddenly discovered in a patient without clinical risk factors, it is better to perform biopsy first to prevent unnecessary surgery.