Case report Hepatic angiomyolipoma: identification of an efferent vessel to be hepatic vein by contrast-enhanced harmonic ultrasound 1 R Q ZHENG, MD, PhD and 2 M KUDO, MD, PhD 1 Department of Ultrasound, the Third Affiliated Hospital, Sun Yat-sen University, Shipai, Guangzhou 510630, China and 2 Department of Gastroenterology and Hepatology, Kinki University School of Medicine, Osaka-Sayama, Japan Abstract. We report two patients with rare hepatic angiomyolipoma and demonstrate the special tumour haemodynamics with contrast-enhanced harmonic ultrasound. This reliably identified the efferent vessel of the hepatic angiomyolipoma to be the hepatic vein in both cases, which corresponded well with that seen on conventional angiography and CT angiography. This haemodynamic finding may be an important characteristic of hepatic angiomyolipoma, and facilitate the differential diagnosis from other benign and malignant hepatic tumours. Hepatic angiomyolipoma is an extremely rare benign tumour of the liver [1]. With the progress of imaging modalities including CT, MRI and ultrasound (US), the reports have been increasing [1–4]. However, to our knowledge, no reports using contrast-enhanced harmonic US to evaluate tumour haemodynamics of hepatic angio- myolipoma have been published. A single case report [4] using ordinary power Doppler had limitations in depicting tumour vessels. Herein, we report two cases of hepatic angiomyolipoma and demonstrate their special tumour haemodynamics with contrast-enhanced harmonic US. Case reports Two patients with liver mass detected by US and/or CT incidentally were admitted to our hospital. Physical exami- nations, all routine blood examinations and tumour markers including a-fetoprotein (AFP), prothrombin- induced vitamin K absence (PIVKA-II) of both patients were normal at the time of admission. The imaging features of the two patients are described below. Case 1, female, 43 years Abdominal US of a 43-year-old female revealed a heterogeneous hypoechoic nodule mixed with hyperechoic area with an irregular shape and poorly defined margin in the medial segment of the liver (Figure 1a). Colour and power Doppler showed abundant blood signals within the tumour. Contrast-enhanced harmonic US was performed using the Coded Harmonic Angio mode in LOGIQ 700 EXPERT (General Electric Medical System, New York, NY) after administration of an intravenous contrast agent, Levovist (Schering AG, Berlin, Germany). The early arterial phase performed in real time scanning demon- strated tumour vessels, including tumour feeding vessel (Figure 1b). During the late vascular phase, tumour parenchymal stain of the whole nodule was revealed and an efferent vessel was clearly demonstrated flowing from the tumour continuously to the hepatic vein (Figure 1c–f ). Contrast-enhanced three-phase dynamic CT revealed a high-attenuation lesion in the arterial phase and portal venous phase, and iso-attenuation in the delayed phase with an irregular shape. The mass was demonstrated as hypervascular on CT during arteriography (CTA) and tumour perfusion defect on CT during arterial portogra- phy (CTAP). On MRI with superparamagnetic iron oxide (SPIO) enhancement, the tumour was observed as a heterogeneous hyperintensity mass. Digital subtraction angiography (DSA) of the liver demonstrated an irregular hypervascular mass with early venous drainage in the venous phase (Figure 1g); the hepatic vein being the efferent vein of the tumour. Hepatic angiogram also demonstrated multiple small pooling within the liver suggesting multiple small haemangiomas (Figure 1g). According to the imaging characteristics of this nodule, namely a hypervascular nodule with hepatic vein as the efferent vein of the tumour, a benign hypervascular tumour of the liver, either a hepatic adenoma or angiomyolipoma were suspected. The patient underwent surgery for tumour resection with informed consent. The cut surface of the tumour was yellowish mixed with white coloured tissue and foci of haemorrhagic clot (Figure 1h). The mass was ill defined with no fibrous capsule. The surrounding tissues were normal. On operation, multiple small haemangiomas of the liver were also identified. Histologically, there were big vessels and many small thick-walled vessels surrounded by proliferated spindle- shaped tumour cells (Figure 1i), which showed strongly positive for HMB-45 immunohistochemical stain and muscle-specific actin stain. Pathological diagnosis of hepatic angiomyolipoma was confirmed. However, the component of adipose tissue within the tumour was extremely sparse. Case 2, female, 49 years Abdominal US of a 49-year-old female showed a heterogeneous isoechoic lesion mixed with small Received 1 March 2005 and in revised form 21 March 2005, accepted 15 April 2005. The British Journal of Radiology, 78 (2005), 956–960 E 2005 The British Institute of Radiology DOI: 10.1259/bjr/27365821 956 The British Journal of Radiology, October 2005
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