Objective To study the clinicopathologic features of hepatic angiomyolipoma (AML) and to investigate the feasibility of a new antibody A103 as a diagnostic aid for AML Methods Ten cases of AML were retrieved from hospital records and analyzed morphologically Immunohistochemistry was performed on paraffin embedded tissues with a panel of antibodies, including antibody A103 Results There were eight women and two men, with ages ranging from 38-58 years (median 45 7) Clinically, nine cases were asymptomatic and found by imaging techniques None of the patients had associated tuberous sclerosis All tumors were sharply demarcated from the surrounding liver parenchyma Histologically they were composed of a heterogeneous mixture of three components: thick walled blood vessels, spindle or epithelioid smooth muscle cells and adipose tissue All tumors showed a strong immunoreactivity to A103, HMB 45 and smooth muscle actins Follow up information on all 10 cases showed a benign course with no signs of recurrence Conclusions Hepatic AML is a rare mesenchymal tumor of the liver A103 is a promising marker for a pathologic diagnosis of hepatic AML