Liver arteriovenous malformation in Rendu-Osler-Weber disease.

Clinical History

Patient was admitted at our institution with right upper quadrant pain, exertional dyspnoea, melaena, weight loss, haemoglobin reduction (6.5 g/dl), and elevated jugular venous pressure.

Imaging Findings

Patient was admitted at our institution with right upper quadrant pain, exertional dyspnoea, melaena, weight loss, and haemoglobin reduction (6.5 g/dl). On clinical examination he was pale and haemodynamically stable. There was evidence of right ventricular failure with an elevated jugular venous pressure. Colour flow Doppler ultrasound revealed tortuous vessels in both liver lobes and arterio-portal fistulae. All three hepatic veins were markedly dilated. CT angiography demonstrated the presence of arterio-portal fistulae with early opacification of the right portal branch.

Discussion

Hereditary haemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber disease, is an autosomal dominant dysplasia characterised by widespread cutaneous, mucosal, and visceral telangiectases. Telangiectasia is the elementary lesion of HHT. Symptomatic visceral involvement is well recognised, occurring in approximately 25% of patients. The organs most commonly affected are the gastrointestinal tract (15%), lung (5%), central nervous system, and liver. Hepatic involvement is usually in the form of sinusoidal dilatation, fibrosis or cirrhosis, but other vascular abnormalities including cavernous haemangiomata, hepatic artery aneurysms, and arteriovenous or arterioportal fistulae have been described. Liver involvement in Rendu-Osler-Weber disease is defined by the presence of vascular malformations potentially involving all hepatic vessels. The evolution of the vascular lesions is represented by progressive enlargement and creation of multiple direct arteriovenous communications. A model derived by a three-dimensional analysis of the hepatic microvasculature detailed the essential pathologic changes: focal sinusoidal ectasia, abnormal direct communications between hepatic arteriolar branches and ectatic sinusoids (arterio-venous shunts), and large communications between the portal and central veins through ectatic sinusoids (portal-vein shunts). Hepatic vascular malformations can lead to liver enlargement; sinusoidal hypertension secondary to intrahepatic shunts can lead to fibrous tissue deposition with portal and peri-portal fibrosis. The clinical presentation in affected people varies greatly depending on the number, type and location of telangiectases or vascular malformations with potential morbidity and mortality. Congenital vascular malformations, iatrogenic causes, and liver neoplasms may lead to large arterio-portal fistulae. Infrequently, these fistulae themselves cause a rapid development of portal hypertension due to the increased flow and pressure in the portal venous system. The involvement of the biliary tree causes haemobilia and associated acute cholecystitis in some cases. Pulsed and colour Doppler ultrasonography allow a rapid analysis of the flow pattern of hepatic vascular malformations, including direction, turbulence, and velocity. The spectral analysis shows high-velocity flow (even aliased or turbulent) in the hepatic artery and its branches with high diastolic phase due to low parenchymal resistances. Hepatic artery causes pulsatility of portal flow to portal vein shunts, possibly with phasic or continuous reversal. On the other hand, hepatic artery causes significant changes to hepatic vein shunts in the Doppler waveform of the hepatic vein only in severe stages of the disease. Computed tomography shows an enlargement of the hepatic artery which is possibly associated with dilated hepatic and/or portal vein. Dynamic CT scan shows the filling kinetics of the hepatic artery, portal vein, hepatic veins, diffuse intrahepatic telangiectases, arteriovenous and arterio-portal shunting. Currently, angiography is performed to confirm the diagnosis and to assess the correct therapeutic approach (surgical or interventional). Several factors determine the therapeutic approach including the location of fistulae and associated factors of morbidity. In some cases a spontaneous closure of small fistulae has been reported. Due to the development of portal hypertension, even asymptomatic fistulae should be treated. In general, surgery is the procedure of choice

Differential Diagnosis List

Final Diagnosis

Liver arteriovenous malformation in Rendu-Osler-Weber disease.

URL:	https://www.eurorad.org/case/4483
DOI:	10.1594/EURORAD/CASE.4483
ISSN:	1563-4086