Angiomyolipoma of the liver: significance of CT and MR dynamic study

Abstract

Angiomyolipoma is a benign mesenchymal tumor that has been reported frequently in the kidney but rarely in the liver. In the present study, we present four cases of hepatic angiomyolipoma with different radiologic appearances, discuss differential diagnosis, and review previously reported cases. One of our cases was followed for 8 years. Computed tomography (plain, enhanced, and dynamic study), magnetic resonance imaging (T1-weighted spin echo, T2-weighted spin echo, and dynamic study), ultrasonography, and angiography were performed in all cases. Although different radiologic appearances were observed in the tumors, based on different proportions of fat, blood vessels, and muscle, three cases were diagnosed as angiomyolipoma. In one case, it was quite difficult to make radiologic diagnosis; hepatocellular carcinoma with fatty metamorphosis in part was most likely suspected, but histopathological examination revealed angiomyolipoma with few fat elements. In the present study, early and prolonged enhancement of the lesion with the special pattern of time density/intensity curve was significant for angiomyolipoma, and we suggest that preoperative radiologic diagnosis of the lesion is possible in most of the cases. However, it can be quite difficult to distinguish angiomyolipoma from some hepatocellular carcinomas with fatty metamorphosis.

Imaging findings of myomatous-type angiomyolipoma of the liver

“…Even though serum -fetoprotein levels were within normal limits and the patient had no history of chronic liver disease, this behavior was suspicious for hepatocellular carcinoma. As described by Ahmadi et al (16), AML can demonstrate early intense contrast enhancement that peaks later than that of hepatocellular carcinoma. Dynamic contrastenhanced CT or MRI obtained during the early phase of enhancement may be useful in discriminating between AML and fat-containing hepatocellular carcinoma.…”

Karaciğerin Mezenkimal Tümörleri

“…Karaciğer AML'si bazı vakalarda tüberoskle-rozla ilişkili olabilir. AML histolojik olarak yağ içeriğine göre mikst, lipomatöz ve miyomatöz olmak üzere 3 alt tipe ayrılır [12][13][14].…”

“…MRG sinyali tümör içi yağ miktarına göre değişmekle beraber sıklıkla T1A görüntülerde hiperintens ve yağ baskılı T2A görüntülerde ise yüksek yağ miktarına bağlı olarak belirgin sinyal kaybı gösterir (Resim 7) [12][13][14].…”

“…AML'deki yağ dokusu çok iyi kanlandığından HCC'den daha erken fazda kontrast tutarken, HCC'nin yağ bileşeni hemen hemen avasküler olduğundan AML'ye kıyasla daha az kontrastlanma gösterir [12][13][14]. Ancak, böb-rek AML'sine kıyasla karaciğer AML'lerinin %50'si yüksek yağ içermez.…”

Angiomiolipoma epitelioide hepático

“…Según la arquitectura se define un patrón trabecular, pelioide o inflamatorio. El componente muscular liso generalmente presenta una morfología epitelioide aunque se pueden observar otras variantes como la oncocítica y pleomórfica 14 .…”