Liver disease in hereditary hemorrhagic telangiectasia

The role of interventional radiology in treatment of patients with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) also known as Osler-Weber-Rendu disease is a rare autosomal dominant, multi-organ disorder that leads to formation of abnormal vascular connections resulting in devastating and life-threatening complications. Due to its multisystem character, wide range of clinical manifestations and variable expressivity, HHT remains a diagnostic challenge and requires close cooperation of specialists from various medical fields. Interventional radiology plays a key role in the management of this disease, helping maintain the health of HHT patients and minimize the risk of fatal complications. The aim of this article is to review clinical manifestations, diagnostic guidelines and criteria of HHT as well as to present the means of endovascular therapy in the management of HHT patients.

Multidisciplinary coordinated care of hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease)

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease, is a rare disorder with a case prevalence as high as one in 5000, causing arteriovenous malformations in multiple organ systems. HHT is familial with autosomal dominant inheritance, with genetic testing allowing confirmation of the diagnosis in asymptomatic kindreds. Common clinical manifestations are epistaxis and intestinal lesions causing anemia and requiring transfusions. Pulmonary vascular malformations predispose to ischemic stroke and brain abscess and may cause dyspnea and cardiac failure. Brain vascular malformations can cause hemorrhagic stroke and seizures. Rarely, liver arteriovenous malformations can cause hepatic failure. A form of HHT can cause juvenile polyposis syndrome and colon cancer. Specialists in multiple fields may be called to care for one or more aspects of HHT, but few are familiar with evidence-based guidelines for HHT management or see a sufficient number of patients to gain experience with the unique characteristics of the disease. Primary care physicians and specialists are often unaware of the important manifestations of HHT in multiple systems and the thresholds for their screening and appropriate management. To improve familiarity, experience, and coordinated multisystem care for patients with HHT, the Cure HHT Foundation, which advocates for patients and families with this disease, has accredited 29 centers in North America with designated specialists for the evaluation and care of patients with HHT. Team assembly and current screening and management protocols are described as a model for evidence-based, multidisciplinary care in this disease.

Hereditary Hemorrhagic Telangiectasia-A Case Series Experience from a Liver Transplant Center in Romania

Hereditary hemorrhagic telangiectasia (HHT) has significant morbidity due to multiorgan involvement and an unpredictable disease course. We analyzed the data of 14 patients diagnosed with HHT. The case series comprised 14 patients with a median age at presentation of 48 years old (41-74 years). In twelve patients (85.7%), the diagnosis was confirmed by using the Curacao Criteria. The most common reason for admission was epistaxis, with 9 patients (57%) presenting with nosebleed refractory to prolonged self-tamponade. The biochemical abnormalities identified were elevations in AP and gamma-GT; liver synthetic function was generally normal, even though 21% of patients had clinical or imaging findings for cirrhosis. Nosebleeds were the main reason for admission and significantly impacted quality of life through anemia and frequent hospital admissions. However, the visceral manifestations seemed to be more serious. The hepatic arteriovenous malformations (AVMs) appeared to remain asymptomatic or led to minimal changes for the majority of patients; some cases were associated with liver and biliary tract ischemia, necrosis leading to acute liver failure and even death. Hepatic AVMs can also lead to high-output heart failure due to arterio-venous shunting. The most frequent AVM was hepatic artery to hepatic vein, with secondary hepatic vein dilation and hemodynamic consequences.

Role of Endoglin (CD105) in the Progression of Hepatocellular Carcinoma and Anti-Angiogenic Therapy

The liver is perfused by both arterial and venous blood, with a resulting abnormal microenvironment selecting for more-aggressive malignancies. Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, the sixth most common cancer globally, and the third leading cause of cancer-related mortality worldwide. HCC is characterized by its hypervascularization. Improving the efficiency of anti-angiogenic treatment and mitigation of anti-angiogenic drug resistance are the top priorities in the development of non-surgical HCC therapies. Endoglin (CD105), a transmembrane glycoprotein, is one of the transforming growth factor β (TGF-β) co-receptors. Involvement of that protein in angiogenesis of solid tumours is well documented. Endoglin is a marker of activated endothelial cells (ECs), and is preferentially expressed in the angiogenic endothelium of solid tumours, including HCC. HCC is associated with changes in CD105-positive ECs within and around the tumour. The large spectrum of endoglin effects in the liver is cell-type- and HCC- stage-specific. High expression of endoglin in non-tumour tissue suggests that this microenvironment might play an especially important role in the progression of HCC. Evaluation of tissue expression, as well as serum concentrations of this glycoprotein in HCC, tends to confirm its role as an important biomarker in HCC diagnosis and prognosis. The role of endoglin in liver fibrosis and HCC progression also makes it an attractive therapeutic target. Despite these facts, the exact molecular mechanisms of endoglin functioning in hepatocarcinogenesis are still poorly understood. This review summarizes the current data concerning the role and signalling pathways of endoglin in hepatocellular carcinoma development and progression, and provides an overview of the strategies available for a specific targeting of CD105 in anti-angiogenic therapy in HCC.

Endoglin in human liver disease and murine models of liver fibrosis-A protective factor against liver fibrosis

BACKGROUND & AIMS

Liver fibrosis is the outcome of chronic liver injury. Transforming growth factor-β (TGF-β) is a major profibrogenic cytokine modulating hepatic stellate cell (HSC) activation and extracellular matrix homeostasis. This study analyses the effect of Endoglin (Eng), a TGF-β type III auxiliary receptor, on fibrogenesis in two models of liver injury by HSC-specific endoglin deletion.

METHODS

Eng expression was measured in human and murine samples of liver injury. After generating GFAP^Cre(+) Eng^ΔHSC mice, the impact of Endoglin deletion on chronic liver fibrosis was analysed. For in vitro analysis, Eng^flox/flox HSCs were infected with Cre-expressing virus to deplete Endoglin and fibrogenic responses were analysed.

RESULTS

Endoglin is upregulated in human liver injury. The receptor is expressed in liver tissues and mesenchymal liver cells with much higher abundance of the L-Eng splice variant. Comparing GFAP^Cre(-) Eng^f/f to GFAP^Cre(+) Eng^ΔHSC mice in toxic liver injury, livers of GFAP^Cre(+) Eng^ΔHSC mice showed 39.9% (P < .01) higher Hydroxyproline content compared to GFAP^Cre(-) Eng^f/f littermates. Sirius Red staining underlined these findings, showing 58.8% (P < .05) more Collagen deposition in livers of GFAP^Cre(+) Eng^ΔHSC mice. Similar results were obtained in mice subjected to cholestatic injury.

CONCLUSION

Endoglin isoforms are differentially upregulated in liver samples of patients with chronic and acute liver injury. Endoglin deficiency in HSC significantly aggravates fibrosis in response to injury in two different murine models of liver fibrosis and increases α-SMA and fibronectin expression in vitro. This suggests that Endoglin protects against fibrotic injury, likely through modulation of TGF-β signalling.

Osler-Weber-Rendu disease presenting as recurrent portosystemic encephalopathy in a 75-year-old female patient

Osler-Weber-Rendu disease is a rare autosomal dominant disorder of fibrovascular tissues, characterized by a classic triad of mucocutaneous telangiectasias, recurrent hemorrhages, and a familial occurrence. Portosystemic encephalopathy in a patient with Osler-Weber-Rendu disease is rare, but we experienced a case presenting with recurrent portosystemic encephalopathy in Osler-Weber-Rendu disease. We report on a case of a 75-year-old female presenting with an altered mentality. Initial studies including brain imaging study did not reveal any specific cause for her mental status. She was diagnosed with the rare disease after a series of tests and received conservative treatment. Her neurological status recovered fully without complication after conservative treatment and she was discharged after 18 hospital days. This case demonstrated an extremely rare case of Osler-Weber-Rendu disease presenting as portosystemic encephalopathy treated successfully with conservative treatment. For patients who have shown hepatic encephalopathy without a definite cause, we recommend evaluation for the possibility of Osler-Weber-Rendu disease. Conservative treatment based on treatment of advanced liver cirrhosis could be an alternative solution.

Osler-Weber-Rendu disease presenting with hepatocellular carcinoma: radiologic and genetic findings

This is a case report of a 68-year-old man with hepatocellular carcinoma (HCC) accompanied by hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease, and hepatic vascular malformation. HHT is an autosomal dominant disorder of the fibrovascular tissue that is characterized by recurrent epistaxis, mucocutaneous telangiectasias, and visceral arteriovenous malformations. HHT is caused by mutation of the genes involved in the signaling pathway of transforming growth factor-β, which plays an important role in the formation of vascular endothelia. Hepatic involvement has been reported as occurring in 30-73% of patients with HHT. However, symptomatic liver involvement is quite rare, and the representative clinical presentations of HHT in hepatic involvement are high-output heart failure, portal hypertension, nodular regenerative hyperplasia, and symptoms of biliary ischemia. Some cases of HCC in association with HHT have been reported, but are very rare. We present herein the characteristic radiologic and genetic findings of HHT that was diagnosed during the evaluation and treatment of HCC.

MR Imaging of sclerosing cholangitis

MRCP is a non-invasive cholangiographic technique used in detection and characterization of bile ducts abnormalities. MRCP features of primary sclerosing cholangitis are randomly distributed annular strictures alternating with slightly dilated bile ducts. Secondary sclerosing processes including ascending, ischemic, caustic, AIDS-related, eosinophilic and autoimmune cholangitis can mimic PSC at MRCP.

Spontaneous thrombosis of an orbital arteriovenous malformation revealing hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber disease). A case report

Hereditary Haemorrhagic Telangiectasia (HHT) is a genetic disorder responsible for cutaneous or mucosal telangiectasia and arteriovenous malformations (AVMs). The most frequent locations are lung and brain. In contrast, orbital AVMs are very rare. We describe a case of symptomatic orbital arteriovenous malformation due to spontaneous thrombosis. A 65-year-old woman was referred for chronic right eye proptosis associated with dilation of conjunctival vessels with a jellyfish pattern. Right visual acuity was 20/40 and intraocular pressure was 40 mmHg. Personal and familial history of recurrent epistaxis, associated with multiple telangiectasia within lips and palate, led to the diagnosis of HHT. Magnetic resonance imaging (MRI) completed with cerebral angiography found a giant and occluded AVM within the right orbit. Other AVMs were also found in brain and chest, confirming the diagnosis. Antiglaucomatous eyedrops were added to reduce intraocular pressure and a steroid therapy was begun. Two months later, visual acuity decreased in the right eye, due to a central retinal vein thrombosis. In conclusion, Most brain or pulmonary AVM can be treated by embolization. By contrast, this treatment in case of orbital location can lead to central retinal artery and/or central retinal vein occlusion, which may also appear as a spontaneous complication of the orbital AVM. Therapeutic management of orbital AVM is thus not standardized, and the balance between spontaneous and iatrogenic risk of visual loss has to be taken into account.

Dynamic 4D MR angiography versus multislice CT angiography in the evaluation of vascular hepatic involvement in hereditary haemorrhagic telangiectasia

PURPOSE

Hereditary haemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber disease, is a rare autosomal dominant disorder characterised by mucocutaneous or visceral vascular abnormalities that may be widely distributed throughout the cardiovascular system. The purpose of this study was to compare multislice computed tomography angiography (MSCTA) and 4D dynamic contrast-enhanced magnetic resonance angiography (D-MRA) for evaluating vascular hepatic involvement in patients with HHT.

MATERIALS AND METHODS

Fifty-two consecutive HHT patients underwent MSCTA and D-MRA examinations for systematic analysis of vascular visceral involvement. The images from the two techniques were reviewed independently by two expert radiologists to identify the following vascular abnormalities: telangiectases or large vascular masses; perfusion disorders [transient hepatic attenuation differences (THADs)]; hepatic arteriovenous malformations (HAVMs). Data, as well as diameters of the common hepatic artery and portal vein, were compared with Cohen's kappa statistic, Student's t test and receiver operating characteristic (ROC) curve analysis, as appropriate.

RESULTS

Both MSCTA and D-MRA detected one or more of the following hepatic vascular abnormalities in 36/52 cases (telangiectases in 29/52, THADs in 23/52 and HAVMs in 25/52[CE1]). A good concordance was found between the two techniques when determining the type of hepatic shunt (κ=0.9). No statistically significant differences were found when comparing mean common hepatic artery and portal vein diameters (p=0.09 and 0.22, respectively) and their accuracy in predicting HAVMs.

CONCLUSIONS

D-MRA has the same diagnostic accuracy as MSCTA and has the advantage of being less invasive due to the absence of ionising radiation.

Hereditary Hemorrhagic Telangiectasia Presenting as High Output Cardiac Failure during Pregnancy

High-output cardiac failure secondary to hepatic involvement is a rare complication of hereditary hemorrhagic telangiectasia (HHT). Here we report a 43-year-old woman who presented at 29 weeks gestation of her second pregnancy with complications of right-sided heart failure and preterm labor. After delivery via cesarean section, the patient was found to have intrahepatic arteriovenous malformations through non-invasive imaging. Subsequently, a family history of vascular malformations and epistaxis was elucidated and a diagnosis of HHT was made. This case is presented, along with a review of the literature and discussion of hepatic involvement in HHT with particular focus on the pregnant patient.

Arterial embolisation and coiling for high-output heart failure and pulmonary hypertension ınduced by hepatic arteriovenous fistula in a patient with hereditary hemorrhagic telengiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a genetic vascular disorder characterised by epistaxis, telangiectases, and visceral arteriovenous malformations. Hyperdynamic blood flow associated with arteriovenous malformations may lead to pulmonary hypertension, global heart failure, and valvular insufficiencies. We report a patient who had HHT with severe heart failure (New York Heart Association [NYHA] class III-IV) and pulmonary hypertension caused by an hepatic arteriovenous fistula. After successful transarterial embolisation of the right branch of the hepatic artery with polyvinyl alcohol (PVA) particles and coils, 4 to 7 mm in size, the patient was discharged with functional class II (NYHA) heart failure.

CT of nonneoplastic hepatic vascular and perfusion disorders

The unique dual blood supply of the liver (75% portal venous, 25% hepatic arterial) makes multiphase helical computed tomography (CT) a highly suitable technique for hepatic evaluation with imaging in two (arterial and portal venous) or more phases. Multiphase helical CT has become an important tool in the detection and characterization of hepatic tumors. In some situations, hemodynamic changes might mimic neoplastic or inflammatory lesions and evoke diagnostic uncertainty. To confidently identify hepatic conditions such as venous outflow obstruction (Budd-Chiari syndrome), arterioportal shunts, hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome), peliosis hepatis, passive congestion, and hepatic infarction, radiologists must be familiar with the disease-specific CT appearances and related clinical manifestations.

Hereditary hemorrhagic telangiectasia: from epistaxis to life-threatening GI bleeding

Hereditary hemorrhagic telangiectasia (HHT) is a rare inherited disorder characterized by widespread mucosal, dermal, and visceral telangiectasias, which can appear as red spots on the lips, tongue, fingers, nose, or intestines. Recurrent epistaxis is the universal presentation, but almost any organ can be affected. Gastrointestinal (usually stomach and small bowel), oral, and urogenital sites are the most common areas affected, whereas pulmonary arteriovenous fistulae can be the most catastrophic. This disorder can present at age 10, and if present, appears in most people by age 21. Gastrointestinal manifestations can cause minor-to-life-threatening bleeding and can lead to the need for liver transplantation. Therapy for HHT includes laser and Argon treatments, embolization, hormones, and surgery. Family members should be screened to provide early recognition and treatment. Gastroenterology nurses should be aware of this rare but potentially fatal disorder as it can be diagnosed or ruled out in the endoscopy suite.

Gastrointestinal manifestations of dermatologic disorders

The skin and the gastrointestinal tract may be affected concurrently by the same diseases. Pathogenetically, these conditions may be primarily dermatologic diseases involving the gastrointestinal (GI) tract or systemic diseases involving the skin, GI tract, and liver simultaneously. The correct diagnosis of such conditions relies on the ability of the gastroenterologist to recognize the underlying dermatologic disorder. The goal of this clinical review article is to increase gastroenterologists' awareness and understanding of some of these conditions. Case vignettes are presented and the relevant literature reviewed for epidermolysis bullosa, mastocytosis, hereditary hemorrhagic telangiectasia, and melanoma. This review focuses on increasing gastroenterologists' ability to recognize, diagnose, comprehend, and manage patients with these dermatologic conditions who have GI manifestations. Advances in molecular genetics that provide insight into the underlying pathophysiology and histopathology of these lesions are highlighted.

Liver involvement in hereditary hemorrhagic telangiectasia: CT and clinical findings do not correlate in symptomatic patients

OBJECTIVE

The purpose of our study was to report the multiphasic CT findings in patients with symptomatic liver involvement by hereditary hemorrhagic telangiectasia (HHT) and to correlate the CT findings with the type of clinical presentation.

CONCLUSION

Patients with symptomatic HHT liver disease have diffuse hepatic telangiectases, a dilated common hepatic artery, and a high incidence of biliary abnormalities. Multiphasic CT is useful in diagnosing liver involvement due to HHT; however, no strong correlation was seen between CT findings and the clinical subtype of HHT liver disease.

Endothelial expression of constitutively active Notch4 elicits reversible arteriovenous malformations in adult mice

Direct communication between arteries and veins without intervening capillary beds is the primary pathology of arteriovenous malformations (AVMs). Although Notch signaling is implicated in embryonic arteriovenous (AV) differentiation, its function in the adult mammalian vasculature has not been established due to the embryonic lethality that often occurs in both gain- and loss-of-function mutants. We expressed a constitutively active Notch4, int3, in the adult mouse endothelium by using the tetracycline-repressible system to suppress int3 during embryogenesis. int3 caused profound blood vessel enlargement and AV shunting, which are hallmarks of AVM, and led to lethality within weeks of its expression. Vessel enlargement, a manifestation of AVM, occurred in an apparently tissue-specific fashion; the liver, uterus, and skin were affected. int3-mediated vascular defects were accompanied by arterialization, including ectopic venous expression of ephrinB2, increased smooth muscle cells, and up-regulation of endogenous Notch signaling. Remarkably, the defective vessels and illness were reversed upon repression of int3 expression. Finally, endothelial expression of a constitutively active Notch1 induced similar hepatic vascular lesions. Our results provide gain-of-function evidence that Notch signaling in the adult endothelium is sufficient to render arterial characteristics and lead to AVMs.

Large pulmonary arteriovenous malformation with hyperammonemia

A 45-year-old female presented with generalized fatigue, unaccompanied by other symptoms. Investigation revealed severe anemia due to gastric bleeding, and hereditary hemorrhagic telangiectasia accompanied by a large pulmonary arteriovenous malformation (PAVM). Additionally, the presence of hepatic arteriovenous and portovenous shunts indicated hepatic involvement. In addition to hypoxemia due to right-to-left shunting in PAVM, hyperammonemia with normal hepatic function was detected. The large PAVM was successfully managed with surgical resection. Hyperammonemia, persisting despite the hemostasis of gastric bleeding, improved postoperatively in the absence of treatment directed at hepatic involvement. We believe that resection of large PAVM contributed to the improvement of hyperammonemia.

Hereditary Vascular Anomalies

Increased understanding of the mechanisms of angiogenesis and lymphangiogenesis has provided a glimpse at some of the molecules involved in the pathophysiology of hemangiomas and vascular malformations. This review focuses on recent advances in our understanding of the mechanisms of angiogenesis/lymphangiogenesis and the differentiation of arterial, venous, and lymphatic vessels. We integrate this knowledge with new data obtained from genetic studies in humans, which have revealed a number of heretofore-unsuspected candidates involved in the development of familial vascular anomalies. We present a common infantile vascular tumor, hemangioma, and then focus on hereditary familial vascular and lymphatic malformations. We also summarize transgenic mouse models for some of these malformations. It seems reasonable to believe that novel therapeutic strategies will soon emerge for the treatment of hemangiomas and vascular malformations.

Hepatic artery embolization for treatment of patients with hereditary hemorrhagic telangiectasia and symptomatic hepatic vascular malformations

At present there is no established therapy for treating patients with hereditary hemorrhagic telangiectasia (HHT) and symptomatic hepatic involvement. We present the results of a prospective study with 15 consecutive patients who were treated with staged hepatic artery embolization (HAE). Branches of the hepatic artery were selectively catheterized and embolized in stages using polyvinyl alcohol particles (PVA) and platinum microcoils or steel macrocoils. Prophylactic antibiotics, analgesics and anti-emetics were administered after every embolization. Clinical symptomatology and cardiac output were assessed before and after therapy as well as at the end of follow-up (median 28 months; range 10-136 months). Five patients had abdominal pain and four patients had symptoms of portal hypertension. The cardiac output was raised in all patients, with cardiac failure being present in 11 patients. After treatment, pain resolved in all five patients, and portal hypertension improved in two of the four patients. The mean cardiac output decreased significantly ( P<0.001) from 12.57+/-3.27 l/min pre-treatment to 8.36+/-2.60 l/min at the end of follow-up. Symptoms arising from cardiac failure resolved or improved markedly in all but one patient. Cholangitis and/or cholecystitis occurred in three patients of whom two required a cholecystectomy. One patient with pre-existent hepatic cirrhosis died as a complication of the procedure. Staged HAE yields long-term relief of clinical symptoms in patients with HHT and hepatic involvement. Patients with pre-existing hepatic cirrhosis may be poor candidates for HAE.

Hormonal and Antihormonal Therapy for Epistaxis in Hereditary Hemorrhagic Telangiectasia

OBJECTIVES/HYPOTHESIS

Objectives were to assess available information on hormonal therapy for bleeding in hereditary hemorrhagic telangiectasia (HHT), to determine whether there is a role for hormonal therapy as an initial therapeutic option, and to report the second known case of response in HHT to antihormonal therapy.

STUDY DESIGN

Literature review and case report.

METHODS

The literature on hormonal and antihormonal therapy for HHT was reviewed. Medical records for the case reported in the present study were evaluated to confirm the diagnosis and assess responses to surgical and nonsurgical treatments.

RESULTS

All reports of success using hormonal therapy for HHT-related bleeding were either retrospective or uncontrolled with the exception of two. Anecdotal evidence with high-dose estrogen appeared to show success, but serious side effects have discouraged use. One controlled trial found no benefit for intermediate dose, single-agent estrogen. The other controlled trial appeared to show benefit with low-dose estrogen-progesterone in HHT with gastrointestinal tract bleeding and was supported by an uncontrolled study showing efficacy in epistaxis. The case reported in the present study demonstrated long-term cessation of epistaxis with tamoxifen in a postmenopausal woman.

CONCLUSIONS

Systemic estrogen-progesterone at doses used for oral contraception may eliminate bleeding in symptomatic HHT and is a reasonable initial option in fertile women. There is no information on possible effects of lower-dose estrogen-progesterone used in postmenopausal women for hormone replacement therapy. Tamoxifen has dramatically eliminated HHT-related bleeding in two cases. It is well tolerated in postmenopausal women and should be considered for randomized clinical trials.

Visceral manifestations in hereditary haemorrhagic telangiectasia type 2

Hereditary haemorrhagic telangiectasia (HHT) is a genetic vascular disorder characterised by epistaxis, telangiectases, and visceral manifestations. The two known disease types, HHT1 and HHT2, are caused by mutations in the endoglin (ENG) and ALK-1 genes, respectively. A higher frequency of pulmonary arteriovenous malformations (AVMs) has been reported for HHT1 while HHT2 is thought to be associated with a lower penetrance and milder disease manifestations. In this study, we present 10 families with an ALK-1 genotype. Visceral manifestations were detected in 24 (26%) of the 93 HHT2 patients from nine of the families and included gastrointestinal bleeding (14%), intrahepatic shunts (6%), and AVMs in the lung (4%) and brain (3%). Gastrointestinal bleeding, the most frequent visceral manifestation, was reported in six of the 10 families, mostly in patients over the age of 50. These patients also had frequent epistaxis and suffered from anaemia, often requiring blood transfusions. The identification of ALK-1 mutations in subjects with a suspected diagnosis and without clinical signs of HHT argue in favour of a molecular diagnosis. We also analysed the data published on 44 families with HHT2 and conclude that visceral manifestations occur in 26 of these families and affect 30% of HHT2 patients. This is considered an underestimate given incomplete and variable screening for lung, brain, and/or liver involvement in different clinical centres. These findings, however, stress the need for an early diagnosis of HHT that can be useful for the early control of associated visceral involvement.