OBJECTIVETo discuss CT and MRI characteristics of hepatic angiomyolipoma based on pathological findings.

METHODSThe CT and MRI appearances with related pathohistological subtypes of 11 hepatic angiomyolipomas from 10 patients were retrospectively analyzed.

RESULTTen patients with hepatic angiomyolipomas were subcategorized into lipomatous (3 cases), angiomatous (1 case), myomatous (1 case) and mixed (5 cases) subtypes. Lesions of the lipomatous type were mainly composed of adipocytes which could be easily recognized on both CT and MRI. Abnormal vessels were commonly seen in the angiomatous lesions, which showed pronounced enhancement in the early arterial phase and remained higher than or isodense with the normal parenchyma in the portal phase. The myomatous type was predominantly composed of leiomyoid cells mixed with small amount of adipocytes. The mixed type was the most frequent,evenly comprising sheets of epithelioid muscle cells admixed with islands of adipocytes and abnormal vessels, and showing homogeneously low density on plain CT and low signal intensity on T1-weighted,intermediately high signal intensity on T2-weighted MRI scans. On dynamic study with both CT and MRI, the mixed type exhibited obvious enhancement, which retained to some degree during the portal phase.

CONCLUSIONThe discrete CT and MRI appearances of hepatic angiomyolipomas with different pathological subtypes depend on the components of the tumor.