Multiple angiomyolipomata of the liver: a case report

Angiomyolipoma (AML) is a rare benign tumor that occurs most commonly in the kidney. Occasionally it may be found in the liver. Lesions in the liver are usually solitary. Multiple AMLs are extremely rare and are typically seen in patients with tuberous sclerosis. We now report an unusual case of a 46-year-old woman with multiple hepatic AMLs. There were more than 15 lesions distributed predominantly in the right hepatic lobe. The tumors ranged from 0.2 to 6 cm in size and consisted of a variable admixture of proliferating blood vessels, adipose tissue, and smooth muscle. There was no clinical evidence of tuberous sclerosis in this patient. Polymerase chain reaction amplification of the highly polymorphic human androgen receptor gene (HUMARA) was performed and the pattern of X chromosome inactivation was analyzed. Three of the five representative AML nodules showed a preferential loss of one of the two HUMARA alleles indicating a clonal proliferation with involvement of different alleles. Histologic examination of the corresponding lesions showed clonal lesions to be predominantly composed of epithelioid myoid cells while the polyclonal lesions were predominantly composed of adipose tissue. While the histologic diagnosis of AML in a surgical resection specimen is often straightforward, the radiographic, cytologic and intra-operative interpretation of a case with multiple lesions presents a considerable challenge.