Multiple Angiomyolipomata of the Liver: A Case Report

Abstract

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 (HU-MARA) 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 intraoperative interpretation of a case with multiple lesions presents a considerable challenge.

Liver involvement in tuberous sclerosis

“…It has been reported only in 6–10% of cases 4. In the literature, only few cases of symptomatic hepatic angiomyolipomas like in our observation have been reported 2 5. This hepatic involvement can be revealed as in our case by abdominal pain, distension and hepatomegaly 2…”

“…The typical lesions are hypointense in T1-weighted dynamic sequences and hyperintense in T2-weighted images after gadolinium administration 5. However, in some cases, hepatic biopsy will be proposed to exclude malignancy.…”

Multifocal angiomyolipoma affecting the liver and lung without tuberous sclerosis

“…5 Hepatic AML is relatively rare, but to date about 200 cases have been reported in the literature since the first report in 1976 by Ishak. [6][7][8][9] Solitary hepatic AML is not usually associated with TSC, in contrast to multiple or combined AMLs of the kidney and liver. 3 ''The occurrence of angiomyolipoma in the liver and the lung without concurrent incidence in the kidney is extremely rare, and only two such cases have been reported'' AML, lymphangioleiomyomatosis (LAM), and clear cell ''sugar'' tumours of the lung are thought to comprise a class of tumour derived from the perivascular epithelioid cell family.…”

Unusual and rare tumours of the liver

“…48 Smooth muscle cells with epithelioid features may also be seen. Rare tumours may be composed entirely of epithelioid cells 49,50 with abundant eosinophilic to clear cytoplasm, eccentric nuclei and prominent nucleoli, with a solid or trabecular growth pattern, similar to epithelioid AML of the kidney (Figure 7). The cytoplasm may show zonation, with an eosinophilic perinuclear zone and a clear peripheral zone.…”