Clinical characteristics and outcomes of patients with hepatic angiomyolipoma: A literature review

Abstract

First reported in 1976, hepatic angiomyolipoma (HAML) is a rare mesenchymal liver tumor occurring mostly in middle-aged women. Diagnosis of the liver mass is often incidental on abdominal imaging due to the frequent absence of specific symptoms. Nearly 10% of HAMLs are associated with tuberous sclerosis complex. HAML contains variable proportions of blood vessels, smooth muscle cells and adipose tissue, which renders radiological diagnosis hazardous. Cells express positivity for HMB-45 and actin, thus these tumors are integrated into the group of perivascular epithelioid cell tumors. Typically, a HAML appears on magnetic resonance imaging (or computed tomography scan) as a hypervascular solid tumor with fatty areas and with washout, and can easily be misdiagnosed as other liver tumors, particularly hepatocellular carcinoma. The therapeutic strategy is not clearly defined, but surgical resection is indicated for symptomatic patients, for tumors showing an aggressive pattern (i.e., changes in size on imaging or high proliferation activity and atypical epithelioid pattern on liver biopsy), for large (> 5 cm) biopsy-proven HAML, and if doubts remain on imaging or histology. Conservative management may be justified in other conditions, since most cases follow a benign clinical course. In summary, the correct diagnosis of HAML is challenging on imaging and relies mainly on pathological findings.

Keywords: Angiomyolipoma, Liver, Tuberous sclerosis complex, Imaging, Pathology, Potentially malignant

Core Tip: Hepatic angiomyolipoma (HAML) is a rare, but not exceptional, mesenchymal liver tumor. HAML contains variable proportions of blood vessels, smooth muscle cells and adipose tissue, which renders its radiological diagnosis challenging. In most cases, this tumor follows a benign clinical course but more aggressive behavior may complicate management, which remains poorly codified. This review presents the main demographic and histological characteristics of HAML, summarizes reported cases of HAML with spontaneous rupture and aggressive behavior, and finally proposes a pragmatic algorithm for the management of HAML based on the most recent knowledge.