Obliterative portal venopathy without portal hypertension: an underestimated condition

Link between persistent, unexplained gamma-glutamyltransferase elevation and porto-sinusoidal vascular disorder

Background & Aims

Porto-sinusoidal vascular disorder (PSVD) is a group of vascular disorders characterized by lesions involving portal venules and sinusoids, irrespective of the presence of portal hypertension. Liver biopsy is essential for diagnosis. In a single-center study, we demonstrated high rates of PSVD in patients with persistently elevated gamma-glutamyltransferase (GGT). This multicenter study aims to establish PSVD prevalence in a larger dataset of individuals with persistent and unexplained GGT elevation, and to identify associated risk factors.

Methods

The study included all patients who underwent liver biopsy for persistent and unexplained GGT elevation in five Italian hepatology units between March 2015 and December 2021.

Results

A total of 144 patients met the inclusion criteria. The majority were males (76/144, 52.8%) and mean age was 51.9 years (range 19-74). Only 12 (8.3%) had liver stiffness measurements (LSM) >10 kPa, while 7 (4.8%) had ultrasound evidence of portal hypertension. Histological findings were consistent with PSVD in 96 patients (67%). Alternative diagnoses were steatohepatitis in 13 (9%), sarcoidosis in 3 (2%) and congenital hepatic fibrosis in 3 (2%) patients. Histological findings were non-specific in 29 (20%) patients. PSVD was associated with male sex (odds ratio [OR] 2.60, 95% CI 1.13-5.99), LSM <10 kPa (OR 11.05, 95% CI 2.16-56.66) and GGT <200 U/L (OR 2.69, 95% CI 1.22-5.98).

Conclusions

PSVD was the main cause of persistent and unexplained elevation of GGT3. Male sex, LSM <10 kPa and GGT <200 U/L were associated with PSVD. These findings highlight the role of liver biopsy in elucidating the underlying pathology and aiding in the diagnosis of patients with persistent and unexplained GGT elevation.

Impact and implications

In outpatient settings, it is common to encounter individuals with persistent and unexplained gamma-glutamyltransferase elevations. This study reveals, for the first time, a non-negligible prevalence of porto-sinusoidal vascular disorder among these individuals when they undergo liver biopsy. Male sex, liver stiffness measurement <10 kPa, and gamma-glutamyltransferase <200 IU/L predict this histological finding. These results may raise awareness of clinically relevant conditions that may be present in patients with persistent liver enzyme changes, even in the absence of signs of advanced chronic liver disease or portal hypertension. Additionally, the data may encourage further studies in the field of porto-sinusoidal vascular disorder, particularly to define its clinical evolution in patients without signs of portal hypertension at diagnosis.

Porto-sinusoidal Vascular Disease: Classification and Clinical Relevance

Non-cirrhotic portal hypertension (NCPH) is a well-recognized clinico-pathological entity, which is associated with clinical signs and symptoms, imaging, and endoscopic features of portal hypertension (PHT), in absence of cirrhosis. In patients with NCPH without known risk factors of PHT or extrahepatic portal vein thrombosis, the condition is called idiopathic non-cirrhotic portal hypertension (INCPH). There are multiple infectious, immune related causes, systemic diseases, drug and toxin exposures, haematological disorders, and metabolic risk factors that have been associated with this INCPH. However, the causal pathogenesis is still unclear. The Vascular liver disorders interest group group recently proposed porto-sinusoidal vascular disease (PSVD) as a syndromic entity, which provides definite histopathological criteria for diagnosis of NCPH (table 1). The three classical histo-morphological lesions specific for PSVD include obliterative portal venopathy, nodular regenerative hyperplasia, and incomplete septal fibrosis. The PSVD definition includes patients with portal vein thrombosis, PVT, and even those without PHT, thus broadening the scope of diagnosis to include patients who may have presented early, prior to haemodynamic changes consistent with PHT. However, this new diagnosis has pros and cons. The cons include mandating invasive liver biopsy to assess the PSVD histological triad in all patients with NCPH, an erstwhile clinical diagnosis in Asian patients. In addition, the natural history of the subclinical forms of PSVD without PHT and linear progression to develop PHT is unknown yet. In this review, we discuss the diagnosis and treatment of INCPH/PSVD, fallacies and strengths of the old and new schema, pathobiology of this disease, and clinical correlates in an Asian context. Although formulation of standardised diagnostic criteria is useful for comparison of clinical cohorts with INCPH/PSVD, prospective clinical validation in global cohorts is necessary to avoid misclassification of vascular disorders of the liver.

Clinical characteristics and natural history of porto-sinusoidal vascular disease: A cohort study of 234 patients in China

BACKGROUND AND AIMS

Porto-sinusoidal vascular disease (PSVD) is an under-recognized and under-diagnosed disease. The purpose of this study was to investigate the clinical features and prognosis of PSVD.

METHODS

The patients who underwent liver biopsies were analyzed retrospectively. The clinical and pathological data were reviewed and screened according to the latest diagnostic criteria of PSVD.

RESULTS

A total of 234 patients were diagnosed as PSVD, including 103 patients presented with portal hypertension (PH) and 131 patients without PH. At baseline, the alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (GGT) levels were higher in the no-PH group. The liver stiffness increased in the PH group. In histological review, obliterative portal venopathy, sinusoidal dilatation and architectural disturbance were more common in the PH group, while portal tract abnormalities were more widely distributed in the no-PH group. After a median follow-up of 43.6 months, the survival rate of patients with baseline liver decompensation was 76.0%, and that of patients at a liver compensated stage in the PH group was 98.7%. First variceal bleeding occurred in 13.8% of patients with gastric-oesophageal varices. None of the patients in the no-PH group developed portal hypertension during follow-up.

CONCLUSIONS

PSVD can manifest as PH or mild liver enzyme abnormalities. There are significant differences in pathological features among patients with different clinical manifestations. Recurrent ascites are the main cause of death in PSVD patients. However, patients without PH have a slow disease progression, with recurrent elevated GGT levels being their main clinical feature.

The autoimmune landscape of Porto-sinusoidal vascular disorder: What the rheumatologist needs to know

Porto-sinusoidal vascular disorder (PSVD) encompasses a group of vascular disorders characterized by lesions of the portal venules and sinusoids with clinical manifestations ranging from non-specific abnormalities in serum liver enzymes to clinically overt portal hypertension and related complications. Several reports have documented cases of PSVD in patients with systemic autoimmune conditions, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. It is of note that these diseases share specific pathophysiological features with PSVD, including endothelial dysfunction, vascular inflammation, and molecular signatures. This narrative review aims to summarize the current knowledge on the association between PSVD and systemic autoimmune diseases, emphasizing the importance of promptly recognizing this condition in the rheumatological practice, and highlighting the key aspects where further research is necessary from both pathogenic and clinical perspectives.

Evaluation of the histologic and immunohistochemical (CD34, glutamine synthetase) findings in idiopathic non-cirrhotic portal hypertension (INCPH)

AIM

Idiopathic non-cirrhotic portal hypertension (INCPH) is a vascular disorder of uncertain origin. Diagnosis can be challenging on liver biopsy. Despite diverse histomorphologic findings documented in literature, studies on the frequency of these findings are lacking. This study aims to assess both the histomorphologic features and the immunoexpression patterns of CD34 and glutamine synthetase (GS) in liver biopsies and searched for their contribution to the pathologic diagnosis of INCPH.

MATERIALS AND METHODS

Hematoxylin-eosin, CD34, and GS-stained liver needle biopsy sections of 16 patients clinically diagnosed with INCPH were retrospectively analyzed. Histologic findings such as portal vein narrowing, obliteration, or loss were grouped as major findings, while portal vein herniation, hypervascularized portal tracts, and periportal abnormal vessels were grouped as minor findings, and their frequency were evaluated. Periportal endothelial CD34 stained areas were measured via ocular micrometer. The distribution of GS immunoexpression was evaluated. Eighteen healthy liver donor biopsies were evaluated as controls.

RESULTS

In INCPH cases, 58% of portal tracts showed major findings, compared to 15% in the control group (p < 0.001). Minor findings were observed in 16% of INCPH cases and 7% of controls (p = 0.014). The number of portal tracts with histologic findings is significantly higher in INCPH than in control liver biopsies. Abnormal portal tract distribution, like being close to each other, was seen in 75% of INCPH cases but not in controls (p < 0.001). Nodular regenerative hyperplasia (NRH) was present in 31% of cases. Periportal CD34 expression was higher in INCPH, and affected areas were larger than in controls (p < 0.001). Irregular GS staining, i.e. GS staining with patchy distribution in zone 3, and/or periportal and zone 2 hepatocytes, was found in 62% of INCPH cases, while controls showed the usual pattern (p < 0.001).

CONCLUSION

In the biopsy diagnosis of INCPH, in addition to the presence of major histologic findings and the amount of portal tracts displaying these features, the expression of endothelial CD34 in periportal areas, and irregular hepatocellular GS expression can also be considered as supporting feature.

Obliteration of portal venules contributes to portal hypertension in biliary cirrhosis

The effects of the obliteration of portal venules (OPV) in cirrhotic portal hypertension are poorly understood. To investigate its contribution to portal hypertension in biliary cirrhosis and its underlying mechanism, we evaluated OPV using two-dimensional (2D) histopathology in liver explants from patients with biliary atresia (BA, n = 63), primary biliary cholangitis (PBC, n = 18), and hepatitis B-related cirrhosis (Hep-B-cirrhosis, n = 35). Then, three-dimensional (3D) OPV was measured by X-ray phase-contrast CT in two parallel models in rats following bile duct ligation (BDL) or carbon tetrachloride (CCl4) administration, representing biliary cirrhosis and post-necrotic cirrhosis, respectively. The portal pressure was also measured in the two models. Finally, the effects of proliferative bile ducts on OPV were investigated. We found that OPV was significantly more frequent in patients with biliary cirrhosis, including BA (78.57 ± 16.45%) and PBC (60.00 ± 17.15%), than that in Hep-B-cirrhotic patients (29.43 ± 14.94%, p < 0.001). OPV occurred earlier, evidenced by the paired liver biopsy at a Kasai procedure (KP), and was irreversible even after a successful KP in the patients with BA. OPV was also significantly more frequent in the BDL models than in the CCl4 models, as shown by 2D and 3D quantitative analysis. Portal pressure was significantly higher in the BDL model than that in the CCl4 model. With the proliferation of bile ducts, portal venules were compressed and irreversibly occluded, contributing to the earlier and higher portal pressure in biliary cirrhosis. OPV, as a pre-sinusoidal component, plays a key role in the pathogenesis of portal hypertension in biliary cirrhosis. The proliferated bile ducts and ductules gradually take up the 'territory' originally attributed to portal venules and compress the portal venules, which may lead to OPV in biliary cirrhosis. © 2024 The Pathological Society of Great Britain and Ireland.

Exploring the link: Porto-sinusoidal vascular disorder and inflammatory bowel disease - A comprehensive narrative review

Porto-sinusoidal vascular disorder (PSVD) encompasses a group of vascular disorders characterized by lesions involving the portal venules and sinusoids, independent of the presence of portal hypertension (PH), and for which liver biopsy is essential for diagnosis. PSVD has been shown to be common in patients with immune-mediated diseases, including inflammatory bowel disease (IBD). The association between PSVD and the use of thiopurines and thioguanine in patients with IBD has been well established. In addition, research suggests an association between PSVD and IBD, even in cases where patients haven't been exposed to specific medications, probably related to changes in intestinal permeability. The identification and management of patients with known IBD and PSVD is a challenge for gastroenterologists. This narrative review aims to summarize the currently available data on the association between IBD and PSVD and provide practical suggestions for the management of this group of patients.

[Portosinusoidal vascular disorder: A paradigm shift]

The term portosinusoidal vascular disorder (PSVD) refers to a clinical-pathological entity that encompasses those patients with intrahepatic vascular damage without cirrhosis at risk of developing severe complications of portal hypertension. Numerous systemic diseases, genetic disorders, and toxic agents have been associated with this pathology, making its diagnosis an important clinical challenge. The recent description of uniform diagnostic criteria and a better understanding of its pathophysiology will allow for better identification of patients, even in early stages of the disease. Although there is currently no effective etiological treatment available, early diagnosis allows for the development of preventive strategies for some severe complications of portal hypertension.

Dissociation in hepatic vein pressure gradient, liver stiffness measurement and complications in histological subtypes of porto-sinusoidal vascular disease

BACKGROUND AND AIMS

Portosinusoidal vascular disease (PSVD) is a broad term encompassing varied histological patterns with changes in portal tracts and sinusoids without cirrhosis. We aimed to assess whether there is any clinical and pathological difference among the various histological categories of PSVD.

PATIENTS AND METHODS

This study included liver biopsy cases classified as PSVD (2020-2022). Clinical and laboratory parameters were obtained from the electronic records. PSVD cases were histologically categorised as obliterative portal venopathy (OPV), OPV with fibrosis (OPV-F), incomplete septal cirrhosis (ISC), nodular regenerative hyperplasia (NRH), mega sinusoids with fibrosis (MSF) and unclassified. Follow-up complications were recorded.

RESULTS

PSVD categories were OPV (45 (26%)), OPV-F (37 (21.4%)), ISC (20 (11.6%)), NRH (19 (11%)), MSF (19 (11%)) and unclassified (33 (19%)). Elevated hepatic venous pressure gradient (HVPG) was noted in OPV-F (10 (IQR: 12-14.7)) and ISC (12 (IQR: 9-14)) mm Hg with higher fibrosis quantity in liver tissue and elevated procollagen III aminoterminal propeptide, which correlated with HVPG. On immunohistochemistry, OPV-F and ISC showed lesser expression of ADAMT13 in liver biopsies (p<0.001). On follow-up, ascites development was more in OPV-F and ISC than in other categories (p=0.001). Higher liver stiffness measurement (LSM) values were recorded in MSF and NRH, compared with other categories, but it did not correlate with fibrosis in liver biopsy.

CONCLUSIONS

OPV-F and ISC had higher HVPG, fibrosis, and more ascites development on follow-up than the other categories of PSVD, and all are not the same. In contrast, MSF and NRH have spuriously high LSM.

Porto-sinusoidal vascular disorder (PSVD): Application of new diagnostic criteria in a multicenter cohort of patients

BACKGROUND AND AIM

The term porto-sinusoidal vascular disorder (PSVD) was recently proposed to replace that of idiopathic non-cirrhotic portal hypertension (INCPH) to describe patients with typical histological lesions in absence of cirrhosis, irrespective of the presence/absence of portal hypertension (PH), and new diagnostic criteria were defined. The study aimed to compare the applicability between the diagnostic criteria of PSVD and those of INCPH.

MATERIALS AND METHODS

53 patients affected by PSVD were enrolled. Biochemical, clinical, ultrasound and histological data, the presence and type of associated diseases were recorded in a database. According to the new criteria, histological data and signs of PH were divided into specific and non-specific. Percutaneous and transjugular biopsies were compared to establish the usability of the two methods for diagnostic purposes.

RESULTS

In 85% of the patients the diagnosis of PSVD was obtained by applying the first criterion (25 had specific histological signs with specific signs of PH); one patient presented with specific histological signs but no PH. In 8 patients the diagnosis was obtained by applying the second criterion. 19% of patients had portal vein thrombosis. Finally, the prevalence of the various histological lesions was similar between the patients submitted to percutaneous and transjugular liver biopsy.

CONCLUSIONS

The study confirms that the diagnostic criteria of PSVD lead to the inclusion of a greater number of patients than INCPH.

Portosinusoidal Vascular Disorder: A Heretofore Unrecognized Manifestation of Sickle Cell Disease?

Portosinusoidal vascular disorder (PSVD) is a recently proposed histopathologic entity that encompasses a spectrum of often subtle hepatic microvascular lesions and related microarchitectural abnormalities. Clinical manifestations may arise years after histologic diagnosis and include extrahepatic portal vein thrombosis and portal hypertension. While the histopathologic features of PSVD have been associated with numerous clinical conditions, most notably prothrombotic/vasculopathic disorders, PSVD has not yet been described in sickle cell disease. This gap is striking given the central role of microvascular dysfunction in sickle cell disease and well-described patterns of hepatic injury and dysfunction in this population. This case series is the first to explore the prevalence and pathogenesis of PSVD in sickle cell disease. Forty-one diagnostically adequate liver biopsies from patients with sickle cell disease were identified across the archives of 5 tertiary medical centers. All biopsies exhibited at least 1 histopathologic feature associated with PSVD (mean 3.8 features/case). Overall, 90.2% of patients met the criteria for a diagnosis of PSVD based on the presence of specific histopathologic and/or clinical findings. Immunohistochemical stains for von Willebrand factor, CD34, and glutamine synthetase were performed on 36 cases (87.8%). Aberrant (centrilobular sinusoidal) CD34 and von Willebrand factor staining was present in 97.2% and 86.1% of cases, respectively. Glutamine synthetase reactivity was at least mildly decreased in zone 3 hepatocytes in 52.8% of cases. We posit that chronic erythrocyte sickling results in dysfunction and remodeling of the portal microvasculature, culminating in regression of zone 3 hepatocytes. The presence of PSVD may explain, at least in part, the hepatic dysfunction observed in this patient population. These patients may also benefit from extended clinical surveillance for portal hypertension and other complications. While subtle and prone to overdiagnosis, the features of PSVD should be carefully considered when interpreting liver biopsies from patients with sickle cell disease.

Evolving Understanding of Noncirrhotic Portal Hypertension

Although cirrhosis is one of the most common causes of portal hypertension, noncirrhotic portal hypertension can result from hemodynamic perturbations occurring in the prehepatic, intrahepatic, and posthepatic circulation. Intrahepatic portal hypertension can be further subclassified relative to the hepatic sinusoids as presinusoidal, sinusoidal, and postsinusoidal. For many of these differential diagnoses, the etiology is known but the cause of idiopathic noncirrhotic portal hypertension, recently included in porto-sinusoidal vascular disease (PSVD), remains poorly understood. Herein, we discuss the diagnostic pathological features of noncirrhotic portal hypertension, with an emphasis on PSVD.

Molecular Mechanisms Underlying Vascular Liver Diseases: Focus on Thrombosis

Vascular liver disorders (VLDs) comprise a wide spectrum of clinical-pathological entities that primarily affect the hepatic vascular system of both cirrhotic and non-cirrhotic patients. VLDs more frequently involve the portal and the hepatic veins, as well as liver sinusoids, resulting in an imbalance of liver homeostasis with serious consequences, such as the development of portal hypertension and liver fibrosis. Surprisingly, many VLDs are characterized by a prothrombotic phenotype. The molecular mechanisms that cause thrombosis in VLD are only partially explained by the alteration in the Virchow's triad (hypercoagulability, blood stasis, and endothelial damage) and nowadays their pathogenesis is incompletely described and understood. Studies about this topic have been hampered by the low incidence of VLDs in the general population and by the absence of suitable animal models. Recently, the role of coagulation imbalance in liver disease has been postulated as one of the main mechanisms linked to fibrogenesis, so a novel interest in vascular alterations of the liver has been renewed. This review provides a detailed analysis of the current knowledge of molecular mechanisms of VLD. We also focus on the promising role of anticoagulation as a strategy to prevent liver complications and to improve the outcome of these patients.

Paediatric porto-sinusoidal vascular disease: Two different clinical phenotypes with subtle histological differences

BACKGROUND AND AIMS

In paediatrics, porto-sinusoidal vascular disease (PSVD) is relatively unknown and probably underdiagnosed. We aimed to describe clinical phenotypes, histology and outcome of children diagnosed with PSVD.

METHODS

Retrospective multicentre study of children diagnosed with PSVD. Diagnosis of PSVD was based on histopathology reports; liver specimens were re-evaluated by two expert liver pathologists.

RESULTS

Sixty two children diagnosed with PSVD (M/F = 36/26, median age 6.6 years, range 3.3-10.6), from 7 centres, were included. Thirty-six presented with non-cirrhotic portal hypertension, PH, (PH-PSVD Group = 58%) while 26 had a liver biopsy because of chronic elevation of transaminases without PH (noPH-PSVD Group = 42%). On histology review, the two groups differed for the prevalence of obliterative portal venopathy (more prevalent in PH-PSVD, p = 0.005), and hypervascularised portal tracts (more common in noPH-PSVD, p = 0.039), the other histological changes were equally distributed. At multivariate analysis, platelet count ≤185 000/mm³ was the only independent determinant of PH (p < 0.001). After a median follow-up of 7 years (range 3.0-11.2), in PH-PSVD group 3/36 (8%) required TIPS placement, 5/36 (14%) developed pulmonary vascular complications of PH, and 7/36 (19%) required liver transplantation. In noPH-PSVD none progressed to PH nor had complications.

CONCLUSIONS

Paediatric patients with PSVD present with two different clinical phenotypes, one characterised by PH and one by chronic elevation of transaminases without PH. PSVD should be included among the conditions causing isolated hypertransaminasaemia. On histology, the differences between the two groups are subtle. Medium-term outcome is favourable in patients without PH; progression of the disease is observed in those with PH.

Portal vein thrombosis, hepatic decompensation, and survival in patients with porto-sinusoidal vascular disease and portal hypertension

BACKGROUND

Porto-sinusoidal vascular disease (PSVD) is a novel nomenclature to describe non-cirrhotic portal hypertension and characteristic histology without portal vein thrombosis (PVT). It is a more inclusive definition than the previously well-recognized entity idiopathic non-cirrhotic portal hypertension. There is a paucity of data on PSVD patients.

METHODS

A total of 33 patients diagnosed with PSVD and portal hypertension (PH) between 2005 and 2021 were included. Data were retrieved from electronic medical record system and analyzed.

RESULTS

Of the 33 patients, 6 (18%) occurred in post-transplant allograft liver. After a median follow-up of 96 months (interquartile range, IQR [52, 139]), 14 deaths occurred (42%), 4 directly related to decompensated liver disease. The Kaplan-Meier survival estimates at 1, 5, and 10 years were 94%, 87% and 58%. PVT occurred in 10 patients (30%). The Nelson-Aalen cumulative risk estimate for PVT at 1, 5 and 10 years were 16%, 25% and 48%. The median model for end-stage liver disease and Child-Pugh score at initial presentation were 8 (IQR [7-12]) and 5 [5-6], and increased to 13 [8, 18] and 7 [5, 8], respectively, at the end of follow-up. Of the 11 patients who presented with splenomegaly and no specific sign of PH, 7 (64%) developed varices and 3 (27%) ascites at a median follow-up of 100 months.

CONCLUSIONS

PSVD with PH is not a benign entity. Mortality, PVT and hepatic decompensation are common. Patients with PSVD must be closely monitored, including those who only have non-specific clinical signs (e.g., splenomegaly) of PH.

Nodular Regenerative Hyperplasia Is Not a Rare Condition After Liver Transplantation: Incidence, Predictive Factors, and Impact on Survival

BACKGROUND

The objectives of this study were to evaluate incidence and to identify the risk factors of occurrence and the predictive factors of symptomatic forms of nodular regenerative hyperplasia (NRH) after liver transplantation (LT).

METHODS

To identify risk factors of NRH following LT, we included 1648 patients transplanted from 2004 to 2018 and compared the patients developing NRH after LT to those who did not. To identify predictive factors of symptomatic NRH, we selected 115 biopsies displaying NRH and compared symptomatic to asymptomatic forms. Symptomatic NRH was defined as the presence of ascites, esophageal varices, hepatic encephalopathy, portal thrombosis, retransplantation, or death related to NRH.

RESULTS

The incidence of NRH following LT was 5.1%. In multivariate analysis, the independent factor of developing NRH after LT was the donor's age (odds ratio [OR] = 1.02; confidence interval, 1.01-1.03; P = 0.02). Symptomatic forms occurred in 29 (25.2%) patients: 19 (16.5%) patients presented with ascites, 13 (11.3%) with esophageal varices, 4 (3.5%) with hepatic encephalopathy, and 8 (7%) with portal thrombosis. The median period before the onset of symptoms was 8.4 (1.5-11.3) y after LT. The spleen size at diagnosis/before LT ratio (OR = 12.5; 114.17-1.37; P = 0.0252) and thrombectomy during transplantation (OR = 11.17; 1.48-84.11; P = 0.0192) were associated with symptomatic NRH in multivariate analysis.

CONCLUSIONS

NRH following LT is frequent (5.1%) and leads to symptomatic portal hypertension in 25.2% of patients. Using older grafts increases the risk of developing NRH after LT. Clinicians should screen for signs of portal hypertension, particularly in measuring spleen size.

Obliterative portal venopathy: A neglected and probably misdiagnosed disease with peculiar etiology in South America

Background and Aim

Obliterative portal venopathy (OPV) is one of the causes of non-cirrhotic portal hypertension. However, many aspects of OPV remain unclear, including the etiology, pathogenesis, and natural history. The aim of this study was to describe the clinical features of OPV in a series of patients in Brazil in whom OPV was diagnosed through liver biopsy.

Methods

Forty-three consecutive adult patients with OPV were retrospectively selected as a case series based on histologic criteria, defined by the presence of at least portal fibrosis, phlebosclerosis, disappearance and/or reduction of the caliber of portal vein branches, and exclusion of cirrhosis. Clinical and laboratory data were analyzed. Clinically significant portal hypertension was considered in the presence of esophageal varices and/or ascites.

Results

The mean age of patients at diagnosis was 44.5 ± 11 years, who were predominantly female (81%). Clinically significant portal hypertension was found in 28% of cases. The most frequent indication for liver biopsy was the elevation of liver enzymes, mostly γ-glutamyl transferase (GGT) in 76% of patients, averaging 222 IU/L (upper limit of normality up to 40 IU/L) and alanine aminotransferase (ALT) in 64%, mean 84 IU/L (38 IU/L). One-third of our patients had exposure to medications, especially herbal medicines, at the time of enzymatic changes. Other risk factors highlighted were features of autoimmunity in 25% of patients or thrombophilia in 20%.

Conclusion

OPV can be diagnosed even before the onset of portal hypertension, ALT elevation, and especially GGT elevation in most cases. Its etiology is not defined, but autoimmune diseases, thrombophilia, and the use of medications or herbal medicines may play a role.

Porto-sinusoidal vascular disorder

It is well established that portal hypertension can occur in the absence of cirrhosis, as reported in patients with immune disorders, infections and thrombophilia. However, similar histological abnormalities primarily affecting the hepatic sinusoidal and (peri)portal vasculature have also been observed in patients without portal hypertension. Thus, the term porto-sinusoidal vascular disorder (PSVD) has recently been introduced to describe a group of vascular diseases of the liver featuring lesions encompassing the portal venules and sinusoids, irrespective of the presence/absence of portal hypertension. Liver biopsy is fundamental for PSVD diagnosis. Specific histology findings include nodular regenerative hyperplasia, obliterative portal venopathy/portal vein stenosis and incomplete septal fibrosis/cirrhosis. Since other conditions including alcohol-related and non-alcoholic fatty liver disease, or viral hepatitis, or the presence of portal vein thrombosis may occur in patients with PSVD, their relative contribution to liver damage should be carefully assessed. In addition to histology and clinical diagnostic criteria, imaging and non-invasive tests such as liver and spleen stiffness measurements could aid in the diagnostic workup. The introduction of PSVD as a novel clinical entity will facilitate collaborative studies and investigations into the underlying molecular pathomechanisms encompassed by this term.

Porto-Sinusoidal Vascular Disease: A Pediatric Study of 30 Patients

OBJECTIVES

Porto-sinusoidal vascular disease (PSVD) refers to a broad spectrum of histological lesions and phenotypic expressions. There are only a few reported pediatric cases in the literature. The primary outcomes of this study were to describe the phenotype of children with PSVD, to specify their mode of presentation and their clinical, biological, histological, and radiological characteristics as well as to identify their underlying etiologies.

METHODS

This is a descriptive, retrospective, and monocentric study of children followed at our reference center for rare vascular liver diseases.

RESULTS

Our study included 30 children ages 2months to 17.4years at the time of diagnosis. in most cases, the diagnosis was made incidentally without manifestation of any clinical symptom but rather on the finding of splenomegaly on physical examination (n = 9) or biological abnormalities (n = 13). In the other cases, the main presenting symptom was an upper gastrointestinal bleeding (n = 6). At the first visit, liver laboratory values were either normal (37%) or slightly disturbed. Anemia and/or thrombocytopenia associated with hypersplenism were found in 60% of patients. Liver biopsy was necessary for diagnosis. A total of 80% of cases had no identified etiology. After a median follow-up of 4.5 years, 33% had not developed portal hypertension (PHT) and we reported the first pediatric case of hepatocellular carcinoma in PSVD children.

CONCLUSIONS

PSVD is responsible for nonspecific symptomatology with variable evolution sometimes marked by serious complications requiring invasive treatments or even liver transplantation. Regular monitoring is essential to prevent, detect, and treat complications.

Evaluation of Liver Histopathological Findings of Coronavirus Disease 2019 by Minimally Invasive Autopsies

AIM

The severe acute respiratory syndrome coronavirus 2 outbreak resulted in severe health impact with the loss of many lives across the world. Pulmonary parenchyma suffers the most from the brunt of the infection. However, evidence suggested a systemic involvement during the course of illness. Information on morphological changes of the liver is sparse in the literature. We aimed to evaluate the pathological findings in the liver by minimally invasive autopsies.

METHODS

Postmortem core biopsies of the liver obtained from patients who succumbed to coronavirus disease 2019 disease were studied. Demographic findings, comorbidities, and relevant laboratory tests were collected. Detailed histopathological changes were assessed.

RESULTS

Liver function tests were available in 40 cases, and it was deranged in 80% cases. A spectrum of histological changes was observed. Macrovesicular steatosis and nonspecific portal inflammation of mild degree were the common morphological changes. Features suggestive of vascular alteration were noted in more than half of the cases. These included increased portal vein branches, irregular luminal dilation, and herniation of portal veins into the periportal hepatocytes. In addition, we observed morphological changes attributed to terminal shock-related changes.

CONCLUSION

The present study results highlight that liver parenchyma changes may be related to multiple pathogenic mechanisms. The presence of vascular alteration in portal tracts suggests derangement of hepatic vasculature related to systemic hypercoagulable state induced by the viral infection. It remains to be established if the histological changes are related to direct viral insult or to the systemic response caused by the viral attack.

Obliterative Portal Venopathy Caused by Oral Contraceptive Pills: A Case Report

Oral contraceptive pills (OCPs) have a known prothrombotic effect. Obliterative portal venopathy (OPV) can be seen in patients with underlying hypercoagulability. We present a case of a 19-year-old female patient taking OCPs who presented with obstructive jaundice. Her main concern was pruritis. An extensive workup was done to reach a diagnosis but it came back negative. A liver biopsy showed OPV. This was thought secondary to her OCP use. Her OCPs were discontinued which resulted in a complete resolution of her symptoms and laboratory abnormalities. Cases with a direct relationship between OPV and OCP use are extremely rare. More studies are required to establish a correlation between OPV and OCPs. OPV should be considered in the differential diagnosis among patients with obstructive jaundice without an obvious cause, especially in patients taking OCPs. Treatment is stopping the OCPs with close follow-up to confirm disease resolution.

Identifying Patients at High Risk of Developing Non-Cirrhotic Portal Hypertension

The term porto-sinusoidal vascular disease (PSVD) has been recently proposed to replace the term idiopathic non-cirrhotic portal hypertension (INCPH) to describe patients with or without signs of portal hypertension and typical histological lesions involving the portal venules or sinusoids in the absence of cirrhosis. According to the new definition, the presence of known causes of liver disease as well as of portal vein thrombosis does not rule out PSVD. Therefore, the patients in whom the diagnosis of PSVD is possible are much more than the patients strictly fulfilling the diagnostic criteria for INCPH. In this setting, the clinical challenge for the hepatologist is to identify patients at risk of developing PSVD and to indicate liver biopsy to confirm the diagnosis. We describe some possible scenarios in which PSVD should always be suspected, and we provide some tools useful to reach the diagnosis of PSVD.

HISTOPATHOLOGICAL, CLINICAL AND EPIDEMIOLOGICAL FEATURES OF HEPATOPORTAL SCLEROSIS IN A REFERRAL CENTER FOR LIVER DISEASE IN NORTHEASTERN BRAZIL

BACKGROUND

Hepatoportal sclerosis HPS or obliterative portal venopathy (OPV), one of the differential diagnoses for non-cirrohtic portal hypertension, is characterized by the disappearance of the portal branches, portal and septal fibrosis, perisinusoidal fibrosis and regenerative nodular hyperplasia (RNH). It is a spectral disease that may progress to severe portal hypertension. Its etiopathogenesis is still little understood, especially in Brazil, it has been probably misdiagnosed due to its histopatological similarities with the hepatosplenic form of schistosomiasis.

OBJECTIVE

To analyze the profile of patients with HPS in Northeastern Brazil and to demonstrate the pathological characteristics of HPS.

METHODS

We retrospectively analyzed cases of OPV in liver biopsies and explants from a referral center for liver in Bahia - Brazil. The qualitative and quantitative analysis of the portal tracts and liver parenchyma was made so that comparisons could be done among the HPS findings of our population and the findings described by other authors.

RESULTS

From the 62 patients identified with HPS, 42% were male, while 58% were female. The average age at diagnosis was 48.3 years. From this group, we analyzed the liver biopsy of 10 patients whose diagnosis of schistosomiasis could be ruled out. From these 100% (10/10) presented dense portal fibrosis and portal venous obliteration. Liver parenchymal atrophy was present in 60% (6/10) of the patients, sinusoidal dilation was present in 30% (3/10), the presence of portal septa occurred in 50% (5/10) and dense portal fibrosis in all patients analyzed. Nodular regenerative hyperplasia was found in 30% (3/10) of the patients.

CONCLUSION

HPS seems to be neglected and misdiagnosed in Brazil, due to its similarities with schistossomiasis. In our study dense portal fibrosis, obliteration of the portal vein branches, parenchymal atrophy, sinusoidal dilatation and parenchymal nodular hyperplasia were the main histopathological findings and were similar to that described in other countries.

Idiopathic Non-Cirrhotic Portal Hypertension and Porto-Sinusoidal Vascular Disease: Review of Current Data

Idiopathic non-cirrhotic portal hypertension (INCPH) is a clinicopathologic disease entity characterized by the presence of clinical signs and symptoms of portal hypertension (PH) in the absence of liver cirrhosis or known risk factors accountable for PH. Multiple hematologic, immune-related, infectious, hereditary and metabolic risk factors have been associated with this disorder. Still, the exact etiopathogenesis is largely unknown. The recently proposed porto-sinusoidal vascular disease (PSVD) scheme broadens the spectrum of the disease by also including patients without clinical PH who are found to have similar histopathologic findings on core liver biopsies. Three histomorphologic lesions have been identified as specific for PSVD to include obliterative portal venopathy, nodular regenerative hyperplasia and incomplete septal cirrhosis/fibrosis. However, these findings are often subtle, under-recognized and subjective with low interobserver agreement among pathologists. Additionally, the natural history of the subclinical forms of the disease remains unexplored. The clinical course is more favorable compared to cirrhosis patients, especially in the absence of clinical PH or liver dysfunction. There are no universally accepted guidelines in regard to diagnosis and treatment of INCPH/PSVD. Hence, this review emphasizes the need to raise awareness of this entity by highlighting its complex pathophysiology and clinicopathologic associations. Lastly, formulation of standardized diagnostic criteria with clinical validation is necessary to avoid misclassifying vascular diseases of the liver and to develop and implement targeted therapeutic strategies.

Key histopathologic features in idiopathic noncirrhotic portal hypertension: an interobserver agreement study and proposal for diagnostic criteria

Histologic features of idiopathic noncirrhotic portal hypertension (INCPH), loosely termed as obliterative portal venopathy (OPV), are heterogenous, often subtle, and overlap with other entities. To this date, no consensus histopathologic diagnostic criteria have been established for INCPH. For these reasons, rendering a reproducible consensus histologic diagnosis of OPV on a liver biopsy may often be challenging even for experienced hepatopathologists. We report herein a two-phase interobserver agreement study on the diagnosis of OPV and assessed the relative value of histologic features in 104 liver biopsies in distinguishing between INCPH and non-INCPH with the goal to obtain a consensus on specific practical diagnostic criteria. Six hepatopathologists blinded to clinical information and original pathologic diagnosis reviewed internet-based case study sets with high-resolution whole-slide images. The initial interobserver agreement on OPV was expectedly low, but significantly improved (moderate agreement in most categories) upon adopting a consensus view recognizing portal vein sclerosis as the only strong independent histologic predictor for INCPH, and that contrary to the conventional view, aberrant portal/periportal vessels does not significantly contribute to the positive assignment of OPV status. We propose a three-tiered classification with diagnostic criteria to facilitate the histologic assignment of OPV status for the evaluation of INCPH. Furthermore, we have validated the performance of the proposed criteria either based on histology alone or coupled with clinicopathologic correlation. This classification may aid in practical histologic assessment of liver biopsies with or without portal hypertension and help to improve diagnostic consistency and accuracy.

Causes and Management of Non-cirrhotic Portal Hypertension​

PURPOSE OF THE REVIEW

Non-cirrhotic portal hypertension (NCPH) includes a heterogeneous group of conditions. The aim of this paper is to make an overview on the denominations, diagnostical features and management of porto-sinusoidal vascular disease (PSVD) and chronic portal vein thrombosis (PVT) being the main causes of NCPH in the Western world.

RECENT FINDINGS

The management of NCPH consists in the treatment of associated diseases and of portal hypertension (PH). PH due to PSVD or PVT is managed similarly to PH due to cirrhosis. TIPS placement and liver transplantation are considerable options in patients with refractory variceal bleeding/ascites and with progressive liver failure. Anticoagulation is a cornerstone both in the treatment of thrombosis in PSVD and in the prevention of thrombosis recurrence in patients with portal cavernoma. Physicians should be aware of the existence of PSVD and chronic PVT and actively search them in particular settings. To now, the management of portal hypertension-related complications in NCPH is the same of those of cirrhosis. Large cooperative studies on the natural history of NCPH are necessary to better define its management.

Liver histopathology in severe COVID 19 respiratory failure is suggestive of vascular alterations

SARS2-CoV-2 breakout in Italy caused a huge number of severely ill patients with a serious increase in mortality. Although lungs seem to be the main target of the infection, very few information are available about liver involvement, possibly evocating a systemic disease. Post-mortem wedge liver biopsies from 48 patients died from severe pulmonary COVID-19 disease with respiratory failure were collected from two main hospitals in northern Italy. No patient had clinical symptoms of liver disease or signs of liver failure before and during hospitalization; for each of them liver function tests were available. All liver samples showed minimal inflammation features. Histological pictures compatible with vascular alterations were observed, characterized by increase in number of portal vein branches associated with lumen massive dilatation, partial or complete luminal thrombosis of portal and sinusoidal vessels, fibrosis of portal tract, focally markedly enlarged and fibrotic. SARS-CoV-2 was found in 15 of 22 samples tested by in situ hybridization method. Our preliminary results confirm the clinical impression that liver failure is not a main concern and this organ is not the target of significant inflammatory damage. Histopathological findings are highly suggestive for marked derangement of intrahepatic blood vessel network secondary to systemic changes induced by virus that could target not only lung parenchyma but also cardiovascular system, coagulation cascade and endothelial layer of blood vessels. It still remains unclear if the mentioned changes are directly related to virus infection or if SARS-CoV-2 triggers a series of reactions leading to striking vascular alterations.

Diagnostic challenges in non-cirrhotic portal hypertension - porto sinusoidal vascular disease

Non-cirrhotic portal hypertension consists of a group of diseases characterized by signs and complications of portal hypertension, which differ from cirrhosis through histological alterations, hemodynamic characterization and, clinical outcome. Because of the similarities in clinical presentation and imaging signs, frequently these patients, and particularly those with porto-sinusoidal vascular disease (PSVD), are misdiagnosed as having liver cirrhosis and thus raising difficulties in their diagnosis. The most challenging differentiation to be considered is between PSVD and cirrhosis and, although not pathognomonic, liver biopsy is still the standard of diagnosis. Although they still require extended validation before being broadly used, new non-invasive methods for the diagnosis of porto-sinusoidal vascular disease, like transient elastography, contrast-enhanced ultrasound or metabolomic profiling, have shown promising results. Another issue is the differentiation between PSVD and chronic extrahepatic portal vein obstruction, especially now when it is known that 40% of patients suffering from PSVD develop portal vein thrombosis. In this particular case, once the portal vein thrombosis occurred, the diagnosis of PSVD is impossible according to the current guidelines. Moreover, so far, the differentiation between PSVD and sinusoidal obstruction syndrome has not been clear so far in particular circumstances. In this review we highlighted the diagnostic challenges regarding the PSVD, as well as the current techniques used in the evaluation of these patients.

Porto-sinusoidal vascular disease: proposal and description of a novel entity

Portal hypertension in the absence of portal vein thrombosis and without cirrhosis, but with mild or moderate alterations of liver histology (eg, obliterative venopathy, nodular regenerative hyperplasia, or incomplete septal cirrhosis) is being increasingly recognised. Owing to the heterogeneity of causes and histological findings, a substantial number of terms have been used to describe such idiopathic non-cirrhotic portal hypertension. Patients with the same clinical and histological features exist, but without portal hypertension at the time of diagnosis. Therefore, improved criteria are needed to define this form of liver disease. Here, we propose the term porto-sinusoidal vascular disease, since all lesions found involve the portal venules or sinusoids. The definition of this entity is based on the characteristic absence of cirrhosis with or without signs of portal hypertension or histological lesions. The presence of known causes of liver disease does not rule out porto-sinusoidal vascular disease, but specific causes of vascular liver disease are excluded from its definition. The diagnosis of porto-sinusoidal vascular disease is based on liver biopsy and might include signs specific for portal hypertension with normal or mildly elevated liver stiffness values and no complete portal vein thrombosis. We provide simple diagnostic criteria, because agreement on a uniform nomenclature is an essential requirement for future collaborative studies.

Aberrant von Willebrand factor expression of sinusoidal endothelial cells and quiescence of hepatic stellate cells in nodular regenerative hyperplasia and obliterative portal venopathy

AIMS

Nodular regenerative hyperplasia (NRH) and obliterative portal venopathy (OPV), entities that comprise idiopathic non-cirrhotic portal hypertension (INCPH), are under-recognised diseases of uncertain aetiology and the diagnosis can be easily missed on liver biopsy. The expression of CD34 and von Willebrand factor (vWF) in liver sinusoidal endothelial cells (LSEC) and alpha-smooth muscle actin (ASMA) in hepatic stellate cells (HSCs) is unknown in NRH and OPV. We sought to investigate the pathogenesis and potential immunomarkers that might aid in making the diagnosis of NRH and OPV.

METHODS AND RESULTS

Immunohistochemical (IHC) staining for CD34, vWF and ASMA was performed in clinically and histologically well-characterised NRH (n = 15) and OPV (n = 47) liver specimens. Among the 47 OPV cases, 37 (78.7%) had concurrent features of NRH. CD34 positive staining was mainly confined to small vessels in the portal tracts and LSECs in periportal areas, a finding similar to that in non-NRH/OPV livers. However, expression of vWF in LSECs was positive in the compressed sinusoids of NRH and in a patchy or geographic pattern, particularly prominent in the perivenular areas and dilated sinusoids of OPV cases. HSCs were negative for ASMA in all NRH and OPV cases.

CONCLUSION

Our findings indicate that NRH may be a subtle but common concurrent morphological feature in OPV. The aberrant expression of vWF in LSECs suggests that endothelial injury may play a role in the pathogenesis, which may thus aid in the recognition and diagnosis of NRH and OPV, particularly when confronted with otherwise apparent normal liver histology on needle biopsy.

Noncirrhotic Portal Hypertension: Current and Emerging Perspectives

Idiopathic portal hypertension (IPH) and extrahepatic portal venous obstruction (EHPVO) are prototype noncirrhotic causes of portal hypertension (PHT), characterized by normal hepatic venous pressure gradient, variceal bleeds, and moderate to massive splenomegaly with preserved liver synthetic functions. Infections, toxins, and immunologic, prothrombotic and genetic disorders are possible causes in IPH, whereas prothrombotic and local factors around the portal vein lead to EHPVO. Growth failure, portal biliopathy, and minimal hepatic encephalopathy are long-term concerns in EHPVO. Surgical shunts and transjugular intrahepatic portosystemic shunt resolve the complications secondary to PHT. Meso-Rex shunt is now the standard-of-care surgery in children with EHPVO.

Abdominal Surgery in Patients With Idiopathic Noncirrhotic Portal Hypertension: A Multicenter Retrospective Study

In patients with idiopathic noncirrhotic portal hypertension (INCPH), data on morbidity and mortality of abdominal surgery are scarce. We retrospectively analyzed the charts of patients with INCPH undergoing abdominal surgery within the Vascular Liver Disease Interest Group network. Forty-four patients with biopsy-proven INCPH were included. Twenty-five (57%) patients had one or more extrahepatic conditions related to INCPH, and 16 (36%) had a history of ascites. Forty-five procedures were performed, including 30 that were minor and 15 major. Nine (20%) patients had one or more Dindo-Clavien grade ≥ 3 complication within 1 month after surgery. Sixteen (33%) patients had one or more portal hypertension-related complication within 3 months after surgery. Extrahepatic conditions related to INCPH (P = 0.03) and history of ascites (P = 0.02) were associated with portal hypertension-related complications within 3 months after surgery. Splenectomy was associated with development of portal vein thrombosis after surgery (P = 0.01). Four (9%) patients died within 6 months after surgery. Six-month cumulative risk of death was higher in patients with serum creatinine ≥ 100 μmol/L at surgery (33% versus 0%, P < 0.001). An unfavorable outcome (i.e., either liver or surgical complication or death) occurred in 22 (50%) patients and was associated with the presence of extrahepatic conditions related to INCPH, history of ascites, and serum creatinine ≥ 100 μmol/L: 5% of the patients with none of these features had an unfavorable outcome versus 32% and 64% when one or two or more features were present, respectively. Portal decompression procedures prior to surgery (n = 10) were not associated with postoperative outcome. Conclusion: Patients with INCPH are at high risk of major surgical and portal hypertension-related complications when they harbor extrahepatic conditions related to INCPH, history of ascites, or increased serum creatinine.

Focus on histological abnormalities of intrahepatic vasculature in chronic viral hepatitis

BACKGROUND & AIMS

The histological intrahepatic microvasculature lesions have not been deeply investigated outside the setting of portal hypertension. The aim of this study was to analyse the type and the prevalence of microvasculature abnormalities and their correlation with inflammatory activity, fibrosis stage and tissue markers of fibrogenesis, angiogenesis and oxidative DNA damage in liver biopsies obtained from patients with chronic viral hepatitis.

METHODS

Seventy-four liver biopsies from untreated patients affected by hepatitis B (22 cases) and C (52 cases) were included. The presence of microvascular changes was correlated with (i) the severity of the activity and fibrosis; (ii) immunohistochemical markers of angiogenesis (CD34) and hepatic stellate cells activation (alpha-smooth muscle actin); (iii) a tissue marker of oxidative damage (8-OHdG adducts).

RESULTS

Sixty-five out of 74 biopsies (87.8%) showed vascular lesions. Portal angiomatosis was the most prevalent (62.2%) and it was associated with, on 1 side, the fibrosis stage at both univariate (P < .0001) and multivariate analysis (P = .01, OR = 9.4 [1.6-54]) and, on the other, with angiogenesis (P = .05) and hepatic stellate cells activation (P = .002). Interestingly, 36/46 cases with portal angiomatosis were at early/intermediate fibrosis stage. The hepatic stellate cells activation was also associated with the presence of aberrant periportal vessels (P = .01).

CONCLUSIONS

The histological alterations of intrahepatic microvasculature, usually seen in cirrhosis and portal hypertension, occur in chronic viral hepatitis even at early/intermediate fibrosis stages. Their correlation with angiogenesis and fibrogenesis supports a possible involvement in disease progression.

Vascular tumours of the liver: a particular story

Vascular tumours of the liver represent an underrated chapter of medical and surgical hepatology. These tumours cover a wide spectrum ranging from the frequent and most benign hepatic haemangioma (HH), via the rare and intermediately aggressive hepatic epithelioid haemangioendothelioma (HEHE) to the rare and most malignant hepatic haemangiosarcoma (HHS). In contrast to the treatment algorithms for hepatocellular and cholangiocellular cancer, the diagnostic and therapeutic approaches to HEHE and HHS are not well developed. The related uncertainty is explained by their rare occurrence and their protean clinical, morphological (imaging) and histopathological presentation and behaviour. This article gives an update about these particular tumours based on the analysis of the recent literature and of the studies on vascular tumours published by the European Liver Intestine Transplantation Association (ELITA)-European Liver Transplant Registry (ELTR). It focuses also on the place of liver transplantation (LT) in the respective therapeutic algorithms. The differential diagnosis between these vascular and other tumour types may be very difficult. Correct diagnosis is of utmost importance and is based on a high index of clinical suspicion and on the integration of clinical, radiological, histological [including immunohistochemistry (IHC) and molecular biology findings]. Surgery, be it partial or total hepatectomy (LT), should be proposed whenever possible, because it is the therapeutic mainstay. In HEHE, LT provides excellent results, with long-term disease-free survivals (DFS) reaching 75%. Good results can be obtained even in case of (frequent) extrahepatic spread. Based on the extensive ELITA-ELTR study a HEHE-LT prognostic score has been proposed in order to estimate the risk of recurrence after LT. In contrast, results of surgery and LT are extremely poor for HHS, for the almost invariably rapid recurrence (within 6 months) and related death within 2 years. LT remains a contraindication for HHS. Due to the still important recurrence rate after surgical resection (25% in HEHE and almost 100% in HHS), there is an urgent need to develop pharmacological treatments targeting angiogenic and non-VEGF angiogenic pathways. To date, some prospective pilot studies and case reports have shown some short-term stabilisation of the disease in small groups of patients. In order to make progress, combination of surgery, anti-angiogenic and immunotherapy seems worthwhile. To complete the panel of vascular liver tumours, infantile haemangioendothelioma, haemangiopericytoma, nodular regenerative hyperplasia (NRH) and hepatic small vessel neoplasms (HSVN) are also discussed.

Non-cirrhotic portal hypertension: an imaging review

Non-cirrhotic portal hypertension (NCPH) comprises a group of diseases that are characterized by increased portal pressure in the absence of cirrhosis of the liver. It may arise as a result of either primary hepatic disease or the effects of systemic disorders on liver. The natural course of NCPH is largely indolent and benign with an overall better outcome than cirrhosis, as long as the complications of portal hypertension are properly managed and regular surveillance is carried out. However, due to the numerous and variable etiological factors and lack of standardized diagnostic criteria, this entity is under-recognized clinically as well as pathologically and often gets mislabeled as cryptogenic cirrhosis. Therefore, it is imperative for radiologists to be aware of the imaging features of various entities that constitute NCPH to facilitate early recognition of this disorder. The present review shall comprehensively discuss the role of imaging in the diagnosis of obliterative portal venopathy, which is a common and one of the most poorly understood disorders leading to NCPH. The other radiologically relevant entities will also be briefly appraised.

Hepatocellular nodules in vascular liver diseases

Hepatocellular nodules have been recognized in vascular liver diseases for a long time and mostly described and studied in the imaging literature. Some confusions in their identification and overlap in their definitions exist, especially in this specific clinical context. Pathology descriptions report the development of nodular regenerative hyperplasia, large regenerative nodule, and focal nodular hyperplasia, as adaptive responses of the liver parenchyma to the modified blood flow. True neoplastic hepatocellular nodules such as hepatocellular adenoma and hepatocellular carcinoma can also appear, mainly in Budd-Chiari syndrome, and have to be correctly diagnosed. This is more difficult for the radiologist in these diseased livers, leading more frequently to perform liver biopsies. We describe the histology of each type of well-differentiated hepatocellular nodules and provide some clues for their differential diagnosis. A review of the literature gives an historical perspective of the problem and enlightens the frequency and the subtypes of hepatocellular nodules found in the most common vascular liver diseases.

Vascular liver diseases on the clinical side: definitions and diagnosis, new concepts

The components of the hepatic vascular system (hepatic arteries, portal and hepatic veins, sinusoids, and lymphatics) can be damaged by various types of injury. Each of the resulting conditions is rare, which has limited knowledge and awareness. In the last two decades, international collaborations have allowed to reach critical masses of data, which has driven significant progresses in understanding and management of vascular disorders of the liver. The present paper discusses definitions, denominations, and diagnosis of such vascular disorders with the exception of those affecting hepatic arteries. Evolving pathogenic or pathophysiologic views relevant to the clinical aspects are also overviewed.

Idiopathic portal hypertension and extrahepatic portal venous obstruction

BACKGROUND

Idiopathic portal hypertension (IPH) and extrahepatic portal venous obstruction (EHPVO) are non-cirrhotic vascular causes of portal hypertension (PHT). Variceal bleed and splenomegaly are the commonest presentations.

AIM

The present review is intended to provide the existing literature on etiopathogenesis, clinical profile, diagnosis, natural history and management of IPH and EHPVO.

RESULTS

IPH and EHPVO are both characterized by normal hepatic venous pressure gradient, moderate to massive splenomegaly with preserved liver synthetic functions. While the level of block in IPH is presinusoidal, in EHPVO it is at prehepatic level. Infections, autoimmunity, drugs, immunodeficiency and prothrombotic states are possible etiological agents in IPH. Contrastingly in EHPVO, prothrombotic disorders and local factors around the portal vein are the incriminating factors. Diagnosis is often clinical, supported by simple radiological tools. Natural history is defined by episodes of variceal bleed and symptoms related to enlarged spleen. Growth failure, portal biliopathy and minimal hepatic encephalopathy are additional concerns in EHPVO. Long-term survival is reasonably good with endoscopic surveillance; however, parenchymal extinction leading to decompensation is seen in a minority of patients in both the disorders. Surgical shunts revert the complications secondary to PHT. Meso-Rex shunt has become the standard surgery in children with EHPVO.

CONCLUSION

This review gives a detailed summary of these two vascular conditions of liver-IPH and EHPVO. Further research is needed to understand the pathogenesis and natural history of these disorders.

Idiopathic noncirrhotic portal hypertension: current perspectives

The term idiopathic noncirrhotic portal hypertension (INCPH) has been recently proposed to replace terms, such as hepatoportal sclerosis, idiopathic portal hypertension, incomplete septal cirrhosis, and nodular regenerative hyperplasia, used to describe patients with a hepatic presinusoidal cause of portal hypertension of unknown etiology, characterized by features of portal hypertension (esophageal varices, nonmalignant ascites, porto-venous collaterals), splenomegaly, patent portal, and hepatic veins and no clinical and histological signs of cirrhosis. Physicians should learn to look for this condition in a number of clinical settings, including cryptogenic cirrhosis, a disease known to be associated with INCPH, drug administration, and even chronic alterations in liver function tests. Once INCPH is clinically suspected, liver histology becomes mandatory for the correct diagnosis. However, pathologists should be familiar with the histological features of INCPH, especially in cases in which histology is not only requested to exclude liver cirrhosis.