Nodular regenerative hyperplasia of the liver: an under-recognized cause of portal hypertension in hematological disorders

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.

A rare case of liver regenerative and non-neoplastic lesion resembling a well-differentiated hepatocellular carcinoma

BACKGROUND

Nodular regenerative hyperplasia (NRH) is a rare disease that presents pathologically as diffuse hepatic nodules without fibrous septa. It is believed to be caused by vasculopathy against a background of various systemic diseases, such as hematologic, autoimmune, and drug-induced diseases, with various symptoms. In spite of the recent imaging advances, various atypical cases of nodular lesions are observed in daily clinical practice. Cases that do not completely meet these criteria are referred to as -like or -similar lesions in clinical situations, making it difficult to understand their pathogenesis. We present a case in which two hepatic nodular lesions were noted and difficult to differentiate from malignancy preoperatively. The lesions were laparoscopically resected and a pathological diagnosis with non-neoplastic liver regenerative nodules resembling NRH was made.

CASE PRESENTATION

A 49-year-old man with no alcohol or drug intake and no past medical history was identified as having liver tumors on screening examination without any symptoms. Contrast-enhanced computed tomography (CT) showed two hepatic tumors; approximately 2-cm tumors at S7 and S8. Gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) revealed fat inclusions in their contents. Ethoxybenzyl (EOB) uptake was also observed during the hepatobiliary phase. Based on preoperative examinations, we suspected well-differentiated hepatocellular carcinoma (HCC) and performed laparoscopic S7/8 partial resection for these lesions. Macroscopically, the resected specimens showed a non-cirrhotic yellowish-cut surface containing brownish, ill-defined lesions with irregular borders. Microscopically, these lesions showed zonal necrosis, congestion, and aggregation of hemosiderin-laden macrophages around the central vein. In these areas, the fatty deposition of hepatocytes was lower than that in the surrounding background hepatocytes. Histopathologically, neither neoplastic nor hyperplastic lesions were observed, and he was diagnosed as regenerative hepatic change with centrilobular necrosis.

CONCLUSIONS

Considering the pathological results, these lesions were thought to be a type of NRH-like lesion with possible hepatic vessel disorder. However, the lesion's cause and classification was difficult to determine. The accumulation of these regenerative changes accompanying fatty liver is needed to clarify the mechanism and its clinical significance.

A Narrative Review on Non-Cirrohotic Portal Hypertension: Not All Portal Hypertensions Mean Cirrhosis

Non-cirrhotic portal hypertension (NCPH), also known as idiopathic non-cirrhotic portal hypertension (INCPH) and porto-sinusoidal vascular disorder (PSVD), is a rare disease characterized by intrahepatic portal hypertension (IPH) in the absence of cirrhosis. The precise etiopathogenesis of IPH is an area of ongoing research. NCPH diagnosis is challenging, as there are no specific tests available to confirm the disease, and a high-quality liver biopsy, detailed clinical information, and an expert pathologist are necessary for diagnosis. Currently, the treatment of NCPH relies on the prevention of complications related to portal hypertension, following current guidelines of cirrhotic portal hypertension. No treatment has been studied that aimed to modify the natural history of the disease; however, transjugular intrahepatic porto-systemic shunt (TIPS) placement, shunt and liver transplantation are considerable symptomatic options. In this review, we discuss the heterogeneity of NCPH as well as its etiopathogenesis, clinical presentation and management issues. Starting from the assumption that portal hypertension does not always mean cirrhosis, cooperative studies are probably needed to clarify the issues of etiology and the possible genetic background of this rare disease. This knowledge might lead to better treatment and perhaps better prevention.

Liver disease accompanied by enteropathy in common variable immunodeficiency: Common pathophysiological mechanisms

Common variable immunodeficiency (CVID) is one of the inborn errors of immunity that have the greatest clinical impact. Rates of morbidity and mortality are higher in patients with CVID who develop liver disease than in those who do not. The main liver disorder in CVID is nodular regenerative hyperplasia (NRH), the cause of which remains unclear and for which there is as yet no treatment. The etiology of liver disease in CVID is determined by analyzing the liver injury and the associated conditions. The objective of this study was to compare CVID patients with and without liver–spleen axis abnormalities in terms of clinical characteristics, as well as to analyze liver and duodenal biopsies from those with portal hypertension (PH), to elucidate the pathophysiology of liver injury. Patients were divided into three groups: Those with liver disease/PH, those with isolated splenomegaly, and those without liver–spleen axis abnormalities. Clinical and biochemical data were collected. Among 141 CVID patients, 46 (32.6%) had liver disease/PH; 27 (19.1%) had isolated splenomegaly; and 68 (48.2%) had no liver–spleen axis abnormalities. Among the liver disease/PH group, patients, even those with mild or no biochemical changes, had clinical manifestations of PH, mainly splenomegaly, thrombocytopenia, and esophageal varices. Duodenal celiac pattern was found to correlate with PH (p < 0.001). We identified NRH in the livers of all patients with PH (n = 11). Lymphocytic infiltration into the duodenal mucosa also correlated with PH. Electron microscopy of liver biopsy specimens showed varying degrees of lymphocytic infiltration and hepatocyte degeneration, which is a probable mechanism of lymphocyte-mediated cytotoxicity against hepatocytes and enterocytes. In comparison with the CVID patients without PH, those with PH were more likely to have lymphadenopathy (p < 0.001), elevated β₂-microglobulin (p < 0.001), low B-lymphocyte counts (p < 0.05), and low natural killer-lymphocyte counts (p < 0.05). In CVID patients, liver disease/PH is common and regular imaging follow-up is necessary. These patients have a distinct immunological phenotype that may predispose to liver and duodenal injury from lymphocyte-mediated cytotoxicity. Further studies could elucidate the cause of this immune-mediated mechanism and its treatment options.

Hepatocyte-specific contrast-enhanced MRI findings of focal nodular hyperplasia-like nodules in the liver following chemotherapy in pediatric cancer patients

PURPOSE

We aimed to assess the MRI findings and follow-up of multiple focal nodular hyperplasia (FNH)- like lesions in pediatric cancer patients diagnosed by imaging findings.

METHODS

We retrospectively analyzed clinical data and MRI examinations of 16 pediatric patients, who had been scanned using gadoxetate disodium (n=13) and gadobenate dimeglumine (n=3). Hepatic nodules were reviewed according to their number, size, contour, T1- and T2-weighted signal intensities, arterial, portal, delayed and hepatobiliary phase enhancement patterns. Follow-up images were evaluated for nodule size, number, and appearance.

RESULTS

All 16 patients received chemotherapy in due course. Time interval between the initial diagnosis of cancer and detection of the hepatic nodule was 2-14 years. Three patients had a single lesion, 13 patients had multiple nodules. The median size of the largest nodules was 19.5 mm (range, 8-41 mm). Among 16 patients that received hepatocyte-specific agents, FNH-like nodules appeared hyperintense in 11 and isointense in 5 on the hepatobiliary phase. During follow-up, increased number and size of the nodules were seen in 4 patients. The nodules showed growth between 6-15 mm.

CONCLUSION

Liver MRI using hepatocyte-specific agents is a significant imaging method for the diagnosis of FNH-like lesions, which can occur in a variety of diseases. Lesions can increase in size and number in pediatric patients.

The continuous rediscovery and the benefit-risk ratio of thioguanine, a comprehensive review

Introduction: In the 1950s, thioguanine (TG), a thiopurine-derivative together with azathioprine (AZA) and mercaptopurine (MP), were developed for the treatment of childhood leukemia. Over the years, the use of TG was also explored for other, mainly immune-mediated and inflammatory, diseases such as in the field of dermatology and rheumatology (e.g. psoriasis, systemic lupus erythematosus (SLE)) and gastroenterology and hepatology (e.g. inflammatory bowel diseases (IBD), autoimmune hepatitis).Areas covered: This review provides a comprehensive overview of all the clinical uses of TG and describes its mechanism of action, pharmacokinetic/pharmacodynamic features, and toxicity.Expert opinion: Thioguanine has shown beneficial clinical effects in hematological (particularly leukemia) and several immune-inflammatory diseases including psoriasis, SLE, polycythemia vera, Churg-Strauss syndrome, IBD, collagenous sprue, refractory celiac disease, and autoimmune hepatitis. Thioguanine is not effective in treating solid-cancers. At relatively low dosages, i.e. 0.2- 0.3mg/kg/day or 20 mg/day, TG has a favorable risk-benefit ratio and is a safe and effective drug in the long-term treatment of amongst other IBD patients. Thioguanine toxicity, especially myelotoxicity, and hepatotoxicity, including nodular regenerative hyperplasia (NRH) of the liver, is limited when dosed adequately. The occurrence of NRH appears dose-dependent and has been especially described during high dose TG above 40 mg/day.

Nodular regenerative hyperplasia - An under-recognized vascular disorder of liver

INTRODUCTION

Nodular regenerative hyperplasia (NRH) is a rare hepatic vascular disorder which is often associated with wide variety of systemic diseases. Intrahepatic microvascular injury and subsequent altered perfusion state leads to development of non-cirrhotic portal hypertension in many of these patients. Diagnosis of NRH often remains unsuspected clinically and liver biopsy is essential for the diagnosis and exclusion of fibrosis. We herein, present clinicopathological features of 22 NRH cases. In addition we assessed CK7 and CD34 expression in hepatocytes and sinusoidal endothelial cells respectively.

RESULTS

Most of the cases were associated with systemic disorders, predominantly immunological, inflammatory and drug-related injuries. Signs and symptoms of portal hypertension were found in 86.4 % patients. Majority of the patients showed a predominant mild cholestatic pattern of liver function tests. Nearly all the (21/22) cases showed CK7 positivity in centrizonal hepatocytes which ranged from <10 % cells to diffuse perivenular positivity extending into the midzonal areas. CD34 positivity in sinusoidal endothelial cells was seen in all the cases, which was prominent in periportal areas in all cases; while perivenular (n = 20) and midzonal (n = 14) areas also showed CD34 positive sinusoidal endothelial cells.

CONCLUSION

This study highlights the role of pathologist in the diagnosis of NRH and stresses upon the need for awareness of NRH as a cause of unexplained portal hypertension in patients with underlying systemic diseases. The altered perfusion state in NRH leads to phenotypic shift in centrizonal atrophic hepatocytes and sinusoidal endothelial cells (as depicted by IHC) which may be responsible for development of portal hypertension.

Clinical Course of Nodular Regenerative Hyperplasia in Thiopurine Treated Inflammatory Bowel Disease Patients

Nodular regenerative hyperplasia (NRH) is a poorly understood liver condition, which is increasingly recognized in thiopurine-treated patients with inflammatory bowel disease (IBD).¹ It is difficult to establish an optimal approach to NRH patients, because its manifestations are highly variable (from asymptomatic to symptoms of noncirrhotic portal hypertension [NCPH]) and the prognosis is unknown.² The aim of this study was to identify NRH cases in IBD patients treated with azathioprine, mercaptopurine, and/or thioguanine, and to describe its clinical course.

Refractory Hepatic Hydrothorax: A Rare Complication of Systemic Sclerosis and Presinusoidal Portal Hypertension

We report on a rare case of refractory hepatic hydrothorax in an individual with Scleroderma/CREST syndrome and noncirrhotic portal hypertension. Portal pressure measurements revealed a normal transjugular hepatic venous portal pressure gradient, mild pulmonary hypertension, and an unremarkable liver biopsy except for mild sinusoidal dilation. Pulmonary hypertension, cardiac diastolic dysfunction, and chronic kidney disease were determined to be the causes of his refractory pleural effusions and ascites. Over the year, he underwent 50 thoracenteses and 20 paracenteses averaging 10-12 liters/week. Repeat pulmonary evaluation determined his pulmonary pressures to be normal and a secondary review of the "unremarkable" liver biopsy noted mild venous outflow obstruction and possibly Nodular Regenerative Hyperplasia (NRH). Repeat portal pressures indirectly and directly confirmed the existence of presinusoidal portal hypertension that has been associated with NRH. A transjugular intrahepatic portal systemic shunt (TIPS) was placed and he has not required thoracentesis or paracentesis over the past 18 months.

Drug-induced Liver Injury: The Hepatic Pathologist's Approach

The evaluation of liver biopsies in suspected drug-induced liver injury (DILI) can be complex. The biopsy may be approached systematically, by identification of histologic lesions and then identification of the overall pattern of injury. Potential DILI must be separated from concomitant non-DILI liver disease. The findings can be analyzed with respect to the various prescription and nonprescription medications and dietary supplements under suspicion to provide a complete interpretation of the findings. The pathologic findings, the histologic differential diagnosis, and expert interpretation are part of a complete biopsy assessment and provide information that is of greatest value in patient management.

Nodular Regenerative Hyperplasia: A Case of Rare Prognosis

Introduction: Nodular regenerative hyperplasia (NRH) is a known etiology of noncirrhotic portal hypertension. Cases of biopsy-proven NRH in human immunodeficiency virus (HIV)-positive patients have been described. While these patients often have normal synthetic liver function, several reports described disease progression to liver failure. Case: We here present a 26-year-old woman with history of congenital HIV on antiretroviral therapy complicated by Pneumocystis carinii pneumonia at age 14. CD4 counts have been >300 with undetectable viral load. She was referred to our Hepatology service for evaluation of splenomegaly, elevated liver tests, and thrombocytopenia. On initial presentation, she reported easy bruising and gingival bleeding, and abdominal imaging showed evidence of portal hypertension without associated cirrhosis. Upper endoscopy was significant for large esophageal varices without bleeding stigmata. Liver biopsy showed minimal fibrosis around the portal areas without significant inflammation. The lobules showed focal zones of thin hepatocyte plates on reticulin stain with adjacent areas showing mild regenerative changes. The diagnosis of NRH was made and patient was placed on propranolol for variceal bleeding prophylaxis. Two years later, the patient presented with bleeding gastric varices warranting transjugular intrahepatic portosystemic shunt. Postprocedure course was complicated by mild encephalopathy. Subsequent magnetic resonance imaging showed a 1.7 × 1.3 cm lesion suggestive of hepatocellular carcinoma (HCC). The patient was deemed to be a candidate for liver transplantation, and she is now delisted due to ongoing pregnancy. Conclusion: This report describes the first case of HCC in an HIV patient with NRH. The possible association of NRH with HCC warrants further investigation.

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.

Liver injury is associated with mortality in sickle cell disease

BACKGROUND

Increased life expectancy in sickle cell disease (SCD) has resulted in greater recognition of the consequences of repeated intravascular vaso-occlusion and chronic haemolysis to multiple organ systems.

AIM

To report the long-term consequences of liver dysfunction in SCD.

METHODS

A cohort of SCD patients was prospectively evaluated at the National Institutes of Health (NIH) Clinical Center. The association of mortality with liver enzymes, parameters of liver synthetic function and iron overload was evaluated using Cox regression.

RESULTS

Exactly, 247 SCD patients were followed up for 30 months of whom 22 (9%) died. After controlling for predictors, increased direct bilirubin (DB), ferritin, alkaline phosphatase and decreased albumin were independently associated with mortality. In a multivariable model, only high DB and ferritin remained significant. Ferritin correlated with hepatic iron content and total blood transfusions but not haemolysis markers. Forty patients underwent liver biopsies and 11 (28%) had fibrosis. Twelve of 26 patients (48%) had portal hypertension by hepatic venous pressure gradient (HVPG) measurements. All patients with advanced liver fibrosis had iron overload; however, most patients (69%) with iron overload were without significant hepatic fibrosis. Ferritin did not correlate with left ventricular dysfunction by echocardiography. DB correlated with bile acid levels suggesting liver pathology. Platelet count and soluble CD14 correlated with HVPG indicating portal hypertension.

CONCLUSIONS

Ferritin and direct bilirubin are independently associated with mortality in sickle cell disease. Ferritin likely relates to transfusional iron overload, while direct bilirubin suggests impairment of hepatic function, possibly impairing patients' ability to tolerate systemic insults.

Liver Transplantation for Acute Intermittent Porphyria: Biochemical and Pathologic Studies of the Explanted Liver

Acute intermittent porphyria (AIP) is an autosomal-dominant hepatic disorder caused by the half-normal activity of hydroxymethylbilane (HMB) synthase. Symptomatic individuals experience life-threatening acute neurovisceral attacks that are precipitated by factors that induce the hepatic expression of 5-aminolevulinic acid synthase 1 (ALAS1), resulting in the marked accumulation of the putative neurotoxic porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Here, we provide the first detailed description of the biochemical and pathologic alterations in the explanted liver of an AIP patient who underwent orthotopic liver transplantation (OLT) due to untreatable and debilitating chronic attacks. After OLT, the recipient's plasma and urinary ALA and PBG rapidly normalized, and her attacks immediately stopped. In the explanted liver, (a) ALAS1 mRNA and activity were elevated approximately ~3- and 5-fold, and ALA and PBG concentrations were increased ~3- and 1,760-fold, respectively; (b) uroporphyrin III concentration was elevated; (c) microsomal heme content was sufficient, and representative cytochrome P450 activities were essentially normal; (d) HMB synthase activity was approximately half-normal (~42%); (e) iron concentration was slightly elevated; and (f) heme oxygenase I mRNA was increased approximately three-fold. Notable pathologic findings included nodular regenerative hyperplasia, previously not reported in AIP livers, and minimal iron deposition, despite the large number of hemin infusions received before OLT. These findings suggest that the neurovisceral symptoms of AIP are not associated with generalized hepatic heme deficiency and support the neurotoxicity of ALA and/or PBG. Additionally, they indicate that substrate inhibition of hepatic HMB synthase activity by PBG is not a pathogenic mechanism in acute attacks.

Rare benign tumors of the liver: still rare?

Background

Benign liver tumors are common. They do not spread to other areas of the body, and they usually do not pose a serious health risk. In fact, in most cases, benign liver tumors are not diagnosed because patients are asymptomatic. When they are detected, it’s usually because the person has had medical imaging tests, such as an ultrasound (US), computed tomography (CT) scan, or magnetic resonance imaging (MRI), for another condition.

Materials and methods

A search of the literature was made using cancer literature and the PubMed, Scopus, and Web of Science (WOS) database for the following keywords: “hepatic benign tumors”, “hepatic cystic tumors”, “polycystic liver disease”, “liver macroregenerative nodules”, “hepatic mesenchymal hamartoma”, “hepatic angiomyolipoma”, “biliary cystadenoma”, and “nodular regenerative hyperplasia”.

Discussion and conclusion

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in some areas of the world; there is an increasing incidence worldwide. Approximately 750,000 new cases are reported per year. More than 75 % of cases occur in the Asia-Pacific region, largely in association with chronic hepatitis B virus (HBV) infection. The incidence of HCC is increasing in the USA and Europe because of the increased incidence of hepatitis C virus (HCV) infection. Unlike the liver HCC, benign tumors are less frequent. However, they represent a chapter always more interesting of liver disease. In fact, a careful differential diagnosis with the forms of malignant tumor is often required in such a way so as to direct the patient to the correct therapy. In conclusion, many of these tumors present with typical features in various imaging studies. On occasions, biopsies are required, and/or surgical removal is needed. In the majority of cases of benign hepatic tumors, no treatment is indicated. The main indication for treatment is the presence of significant clinical symptoms or suspicion of malignancy or fear of malignant transformation.

Downregulation of the endothelial genes Notch1 and ephrinB2 in patients with nodular regenerative hyperplasia

BACKGROUND & AIMS

Nodular regenerative hyperplasia (NRH) is a rare liver disease characterized by small regenerative nodules without fibrosis and can cause portal hypertension. Aetiology and pathogenesis of NRH remain unclear. We have recently shown that Notch1 knockout induces NRH with portal hypertension through vascular remodelling in mice. The aim of this study was to analyse histological and clinical data of NRH patients and to explore if the endothelial pathways identified in our NRH mouse model are also regulated in human NRH.

METHODS

Patients were identified retrospectively from the pathology database. Clinical and laboratory patient data were retrieved. mRNA expression was measured in liver biopsies from a subset of NRH patients.

RESULTS

Diagnosis of NRH was confirmed in needle biopsies of 51 patients, including 31 patients with grade 1, 12 patients with grade 2 and 8 patients with grade 3 NRH. Grade 3 nodularity significantly correlated with the presence of portal hypertension: 50% of the patients with grade 3 NRH vs. 6.5% with grade 1 (P = 0.0105). mRNA expression analysis in liver biopsies from 14 NRH patients and in primary human sinusoidal endothelial cells revealed downregulation of identical genes as in the murine NRH model, which are implicated in vascular differentiation: Notch1, delta-like 4 (Dll4) and ephrinB2.

CONCLUSIONS

In this large NRH needle biopsy cohort, we demonstrated that advanced nodularity correlates with presence of portal hypertension. Downregulation of the endothelial signalling pathways Dll4/Notch1 and ephrinB2/EphB4 supports the hypothesis that human NRH is caused by a sinusoidal injury providing first insights into the molecular pathogenesis of this liver condition.

Immune Components of Liver Damage Associated with Connective Tissue Diseases

Autoimmune connective tissue diseases are associated with liver abnormalities and often have overlapping pathological and clinical manifestations. As a result, they can present great clinical challenges and evoke questions about diagnostic criteria for liver diseases. Moreover, discriminating between liver involvement as a manifestation of connective tissue disease and primary liver disease can be challenging since they share a similar immunological mechanism. Most patients with connective tissue diseases exhibit liver test abnormalities that likely result from coexisting, primary liver diseases, such as fatty liver disease, viral hepatitis, primary biliary cirrhosis, autoimmune hepatitis, and drug-related liver toxicity. Liver damage can be progressive, leading to cirrhosis, complications of portal hypertension, and liver-related death, and, therefore, must be accurately identified. In this review, we highlight the challenges facing the diagnosis of liver damage associated with connective tissue disease and identify immune mechanisms involved in liver damage associated with connective tissue diseases.

Human immunodeficiency virus and nodular regenerative hyperplasia of liver: A systematic review

AIM: To investigate the diagnosis, pathogenesis, natural history, and management of nodular regenerative hyperplasia (NRH) in patients with human immunodeficiency virus (HIV).

METHODS: We performed a systematic review of the medical literature regarding NRH in patients with HIV. Inclusion criteria include reports with biopsy proven NRH. We studied the clinical features of NRH, in particular, related to its presenting manifestation and laboratory values. Combinations of the following keywords were implemented: “nodular regenerative hyperplasia”, “human immunodeficiency virus”, “noncirrhotic portal hypertension”, “idiopathic portal hypertension”, “cryptogenic liver disease”, “highly active antiretroviral therapy” and “didanosine”. The bibliographies of these studies were subsequently searched for any additional relevant publications.

RESULTS: The clinical presentation of patients with NRH varies from patients being completely asymptomatic to the development of portal hypertension – namely esophageal variceal bleeding and ascites. Liver associated enzymes are generally normal and synthetic function well preserved. There is a strong association between the occurrence of NRH and the use of antiviral therapies such as didanosine. The management of NRH revolves around treating the manifestations of portal hypertension. The prognosis of NRH is generally good since liver function is preserved. A high index of suspicion is required to make a identify NRH.

CONCLUSION: The appropriate management of HIV-infected persons with suspected NRH is yet to be outlined. However, NRH is a clinically subtle condition that is difficult to diagnose, and it is important to be able to manage it according to the best available evidence.

Clinical analysis of 15 cases of liver nodular regenerative hyperplasia

Nodular regenerative hyperplasia (NRH) of liver may be one of the leading causes of non-cirrhotic intrahepatic portal hypertension (NCIPH), although the exact relationship is currently unknown. Diagnosis of NRH is relatively difficult and involves surgical pathology, and thus it is necessary to improve the preoperative recognition of NRH. Here, we analyze 15 cases of NRH to better understand this disease. All the liver specimens were microscopically examined by hematoxylin-eosin staining and reticulin and Masson trichrome staining. Diagnoses of NRH were confirmed by pathological examination. Clinically, NRH presents as diffused liver lesions with mildly increased liver enzymes. Portal hypertension is the most common clinical manifestation presenting prominently as splenomegaly, hypersplenism, and esophageal varices bleeding. NRH is often associated with autoimmune or collagen vascular diseases, and such patients often present with a variety of positive autoantibodies and increased erythrocyte sedimentation rate (ESR), Ig and γ %. Pathological examination of the liver showed diffuse small regenerative nodules without fibrous septa and obstructive portal venopathy. For those patients with portal hypertension of unknown cause and preserved liver function, especially, those combined with autoimmune diseases, NRH should be considered.

Portal hypertension from nodular regenerative hyperplasia of the liver treated with distal splenorenal shunt

Portal hypertension (PH) is a devastating sequelae of several pathologic entities, with alcoholic cirrhosis being the most common cause in the western world and endemic schistosomiasis worldwide. A much less common aetiology of non-cirrhotic PH is nodular regenerative hyperplasia (NRH) of the liver. The hallmark of NRH is a benign remodeling of the hepatic parenchyma into regenerative nodules in the absence of fibrosis (1). A Warren-Zeppa Distal Splenorenal Shunt (DSRS) was performed in a young patient with NRH of the liver to alleviate PH. This procedure was chosen due to its low postoperative rates of hepatic insufficiency and high durability.

Evaluation of liver lesions

The differential diagnosis of a liver mass is large and requires understanding of the clinical and imaging features of liver lesions. A detailed history, physical examination, hepatic biochemical tests, and imaging studies are all essential in making the diagnosis. Decisions regarding specific imaging modalities for diagnoses, the use of liver biopsy, therapeutic options, and appropriate follow-up are all determined by the presentation of the lesion and associated patient characteristics.

Liver transplantation for the treatment of nodular regenerative hyperplasia

BACKGROUND

Nodular regenerative hyperplasia (NRH) is the leading cause of non-cirrhotic portal hypertension in Western countries. Although some patients are successfully managed medically or with shunting procedures, others require liver transplantation. The aim of this review was to assess the overall results obtained with liver transplantation and to better define its role in this setting.

METHODS

Systematic review of all published studies on liver transplantation for NRH without language restrictions, in Medline, Embase and Cochrane Library databases through March 2010.

RESULTS

17 studies including a total of 73 patients were identified; 47 (64.3%) were excluded due to lacking inclusion criteria or clinical data and 26 (35.7%) were analysed. Before liver transplantation, the most frequent clinical presentation was gastroesophageal bleeding (65.3%) followed by ascites (61.5%), hepatic encephalopathy (30.7%) and liver failure (11.5%). The mean follow-up reported after liver transplantation was 30.6±27.6 months and patient and graft survival rate was 78.3%. Only one case reported a NRH recurrence 7 years after liver transplantation (LT).

CONCLUSIONS

Although there are no hard data supporting the role of liver transplantation in symptomatic NRH, onset of severe portal hypertension in this setting may represent a valid indication.

Nodular regenerative hyperplasia of the liver: coral atoll-like lesions on ultrasound are characteristic in predisposed patients

Nodular regenerative hyperplasia (NRH) is an uncommon liver disease characterised histologically by numerous small hyperplastic nodules that are not separated by fibrotic tissue. It is thought to be the result of obliterative vasculopathy, and it has been associated with chronic use of medications, toxic substances and a wide variety of systemic diseases. Imaging diagnosis of early-stage NRH remains problematic. The nodules are rarely discerned and their appearance and behaviour before and after contrast medium administration are heterogeneous and not specific. A review of the literature shows that ultrasound has succeeded on occasion in revealing small focal liver lesions in patients with NRH. To our knowledge, there has been no published data on the performance in this setting of last-generation ultrasound scanners and techniques such as contrast-enhanced ultrasound (CEUS). The question is an important one because abdominal ultrasound is widely used as a first-line imaging technique for the evaluation of liver disease, and this makes it particularly suitable as a potential tool for the early diagnosis of NRH. Owing to the prolonged subclinical period and the limited help provided by imaging, the diagnosis in vivo of NRH is currently frequently missed, and it is still made exclusively on the basis of liver biopsy. In conclusion, this report describes 4 cases of biopsy-proven NRH that have been diagnosed over the past 2 years by our group. All were characterised by known comorbidities that confer a predisposition to NRH and by a peculiar parenchymal ultrasound pattern that we refer to as the "atoll sign".

Biologic and clinical features of benign solid and cystic lesions of the liver

The widespread use of imaging analyses, either routinely or to evaluate symptomatic patients, has increased the detection of liver lesions (tumors and cysts) in otherwise healthy individuals. Although some of these incidentally discovered masses are malignant, most are benign and must be included in the differential diagnosis. The management of benign hepatic tumors ranges from conservative to aggressive, depending on the nature of the lesions. New imaging modalities, increased experience of radiologists, improved definition of radiologic characteristics, and a better understanding of the clinical features of these lesions have increased the accuracy of diagnoses and reduced the need for invasive diagnostic tests. These advances have led to constant adjustments in management approaches to benign hepatic lesions. We review the biologic and clinical features of some common hepatic lesions, to guide diagnosis and management strategies.

Hepatic incidentalomas

Recent advances in multidetector-row computed tomography, magnetic resonance imaging, and ultrasonography have led to the detection of incidental hepatic lesions in both the oncology and nononcology patient population that in the past remained undiscovered. These incidental hepatic lesions have created a management dilemma for both clinicians and radiologists. In this review, guidelines concerning the diagnosis and management of some of the more common hepatic incidentalomas are presented.

Nodular regenerative hyperplasia: Evolving concepts on underdiagnosed cause of portal hypertension

Nodular regenerative hyperplasia (NRH) is a rare liver condition characterized by a widespread benign transformation of the hepatic parenchyma into small regenerative nodules. NRH may lead to the development of non-cirrhotic portal hypertension. There are no published systematic population studies on NRH and our current knowledge is limited to case reports and case series. NRH may develop via autoimmune, hematological, infectious, neoplastic, or drug-related causes. The disease is usually asymptomatic, slowly or non-progressive unless complications of portal hypertension develop. Accurate diagnosis is made by histopathology, which demonstrates diffuse micronodular transformation without fibrous septa. Lack of perinuclear collagen tissue distinguishes NRH from typical regenerative nodules in the cirrhotic liver. While the initial treatment is to address the underlying disease, ultimately the therapy is directed to the management of portal hypertension. The prognosis of NRH depends on both the severity of the underlying illness and the prevention of secondary complications of portal hypertension. In this review we detail the epidemiology, pathogenesis, diagnosis, management, and prognosis of NRH.

Sinusoidal obstruction syndrome

Sinusoidal obstruction syndrome (SOS), formerly named venoocclusive disease, is a well-known complication of hematopoietic stem cell transplantation and ingestion of food or drinks contaminated by pyrrolizidine alkaloids. Many other drugs and toxins have been associated with SOS, including several chemotherapeutic agents and immunosuppressors. SOS contributes to significant morbidity and mortality in all these settings. This review describes the histologic lesions of SOS, details its pathogenesis as it is understood today, specifies the recent data on its causes and how it may influence clinical management of colorectal liver metastases, and discusses the current knowledge on diagnosis and preventive options.

Colon Capsule Endoscopy compared to Conventional Colonoscopy under routine screening conditions

Background

Nodular regenerative hyperplasia (NRH) has been recently recognized as an emergent cause of liver disease in HIV-infected patients. NRH may cause non-cirrhotic portal hypertension with potentially severe consequences such as refractory ascites, variceal bleeding and hypersplenism. Obliteration of the small intrahepatic portal veins in association with prothrombotic disorders linked to HIV infection itself or anti-retroviral therapy seem to be the causes of NRH and thus the term HIV-associated obliterative portopathy has been proposed.

Case Presentation

Here we describe a case of a HIV-infected patient with biopsy-proven NRH and listed for liver transplantation (LT) because of refractory ascites and repeated upper gastrointestinal bleedings. A transjugular intrahepatic portosystemic shunt was placed as a bridge to LT and did not improve liver function. However, anticoagulant therapy with low-molecular-weight heparin (LMWH) was associated with rapid improvement in the liver condition and allowed to avoid LT in this patient.

Conclusions

Thus, this case underscores the relation between thrombophilia and HIV-associated NRH and emphasizes anticoagulant therapy as possible treatment.

Usefulness of noninvasive tests in nodular regenerative hyperplasia of the liver

BACKGROUND

The only way to diagnose nodular regenerative hyperplasia (NRH) is liver biopsy.

AIM

To evaluate in a prospective study the performance of noninvasive liver investigations in patients with NRH.

METHODS

All consecutive patients with NRH who were being followed up in our unit from 2004 to 2007 were included. All biopsy specimens were reanalysed independently to confirm the diagnosis of NRH (classified as certain or probable) and to assess portal or sinusoidal associated fibrosis. All patients had liver stiffness (using FibroScan) and FibroTest measurements. Magnetic resonance imaging (MRI) was performed using two contrast agents (gadolinium-chelate and ferucarbotran).

RESULTS

Thirty patients were included (mean age: 53 years). Median liver stiffness value was 7.9 kPa (range: 3.5-16.8), with 63% of the patients having more than 7.1 kPa. No relationship was found between NRH with or without portal hypertension and liver stiffness or Fibrotest. No correlation was found between liver stiffness and portal and/or sinusoidal fibrosis. In patients studied with MRI, 55% had portal hypertension and 9% a diffuse fine-nodular loss of iron uptake after ferucarbotran injection.

CONCLUSION

Liver stiffness and FibroTest values may be increased in NRH patients, with no correlation with portal hypertension or portal and sinusoidal fibrosis. Contrast-enhanced MRI is disappointing in NRH.

Sinusoidal obstruction syndrome and nodular regenerative hyperplasia are frequent oxaliplatin-associated liver lesions and partially prevented by bevacizumab in patients with hepatic colorectal metastasis

AIMS

Because of its efficacy, oxaliplatin (OX) is increasingly used as a chemotherapeutic agent in the treatment of colorectal liver metastases (CRLM). Oxaliplatin-associated liver toxicity has been reported and can affect clinical practice, but studies on its prevalence and a full pathological description are lacking. The aims of this study were to fill this gap by providing, from a pathologist's perspective, a detailed assessment of the spectrum of hepatic lesions associated with OX, to suggest a scoring system to quantify them, and to investigate the protective effect of bevacizumab against OX-associated damage.

METHODS AND RESULTS

The spectrum of oxaliplatin-associated liver lesions was investigated in a multi-institutional series of surgically resected CRLM (n = 385). Among 274 patients treated by OX, 54% had moderate/severe sinusoidal obstruction syndrome (SOS). Peliosis, centrilobular perisinusoidal/venular fibrosis and nodular regenerative hyperplasia (NRH) developed in 10.6%, 47% and 24.5%, respectively. The 111 patients treated by surgery alone had no lesions. Hepatic lesions were less severe in patients treated with OX/bevacizumab (n = 70) compared with the group treated by OX alone (n = 204), with an incidence of moderate/severe SOS (31.4% versus 62.2%), peliosis (4.3% versus 14.6%), NRH (11.4% versus 28.9%, respectively) and centrilobular/venular fibrosis (31.4% versus 52%, respectively) (P < 0.001).

CONCLUSIONS

Pathologists should be aware of the distinctive lesions associated with OX and of their high prevalence. OX-related lesions are less frequent in patients treated with bevacizumab, suggesting that this drug has a preventive effect. Uniform criteria for diagnosis and grading of OX-associated lesions should help to include histological data in the optimal multidisciplinary management of CRLM.

Hepatic nodular regenerative hyperplasia in a patient with advanced carcinoid tumor

Nodular regenerative hyperplasia (NRH) of the liver is a rare disease that is characterized by multiple regenerative nodules in the hepatic parenchyma that may lead to noncirrhotic portal hypertension. The exact pathogenesis of NRH has not been established, but it has been suggested that a primary vascular abnormality causing local ischemia may initiate the nodular transformation. It is also known that this condition is associated with autoimmune disease, hematological disease, and some chemotherapy agents in which vasculopathy is a prominent feature. The patients with NRH are usually asymptomatic unless they develop complications related to portal hypertension. We report a case of a middle-aged female patient with florid carcinoid syndrome, speculating that vasoactive hormones including serotonin secreted by the tumor caused intrahepatic microcirculatory disturbances that eventually induced NRH. This association has not been reported earlier.

Characteristics of common solid liver lesions and recommendations for diagnostic workup

Due to the widespread clinical use of imaging modalities such as ultrasonography, computed tomography and magnetic resonance imaging (MRI), previously unsuspected liver masses are increasingly being found in asymptomatic patients. This review discusses the various characteristics of the most common solid liver lesions and recommends a practical approach for diagnostic workup. Likely diagnoses include hepatocellular carcinoma (the most likely; a solid liver lesion in a cirrhotic liver) and hemangioma (generally presenting as a mass in a non-cirrhotic liver). Focal nodular hyperplasia and hepatic adenoma should be ruled out in young women. In 70% of cases, MRI with gadolinium differentiates between these lesions. Fine needle core biopsy or aspiration, or both, might be required in doubtful cases. If uncertainty persists as to the nature of the lesion, surgical resection is recommended. If the patient is known to have a primary malignancy and the lesion was found at tumor staging or follow up, histology is required only when the nature of the liver lesion is doubtful.

MR imaging of hypervascular liver masses: a review of current techniques

Major technologic advances in magnetic resonance (MR) imaging, including the advent of novel pulse sequences (eg, diffusion-weighted and steady-state free precession sequences) and the use of hepatocyte-specific contrast agents, have led to better image quality and shorter acquisition times, resulting in dramatic improvements in the noninvasive detection and characterization of hepatic lesions, particularly hypervascular neoplasms. However, as the role of MR imaging in clinical evaluation of the liver continues to evolve, keeping abreast of new developments can be daunting as well as confusing. A systematic approach that makes use of a simple decision algorithm can help differentiate hypervascular hepatic lesions on the basis of their distinguishing MR imaging characteristics and related clinical information.

Approach to a liver mass

Incidentally discovered liver masses are becoming more common with the increasing application and power of imaging techniques for the evaluation of abdominal conditions. Although such masses are often benign, conclusive diagnoses must be established in order to provide appropriate patient care. Various imaging modalities can be utilized to accurately diagnose such masses without resort to more invasive diagnostic measures.

Review article: the evaluation of solitary liver masses

BACKGROUND

The increasing use of imaging modalities has led to the detection of more liver masses. The differential diagnosis of a focal liver mass includes a host of benign as well as malignant conditions.

AIM

To provide a comprehensive review on the commonly encountered liver masses, and to help guide an approach to their evaluation and management.

METHODS

Pertinent literature that was identified through PubMed search and senior author's experience formed the basis of this review.

RESULTS

While most incidentally noted liver masses are benign, it may be difficult to differentiate them from those that are malignant. Furthermore, some benign lesions have malignant potential. Certain lesions such as focal nodular hyperplasia, haemangiomas and focal steatosis are often distinctly diagnosed by an imaging modality alone. The less frequently encountered hepatic adenomas are diagnosed radiologically in those with the appropriate clinical background and the absence of radiological features to suggest haemangioma or focal nodular hyperplasia.

CONCLUSIONS

A reasonable approach to the diagnosis, follow-up and management of liver masses is based on a rudimentary knowledge of their presentation, associated clinical and laboratory features, natural history and available treatment options. Most often, the so called 'incidentalomas' are benign and require patient reassurance.

Nodular regenerative hyperplasia of the liver

Nodular regenerative hyperplasia (NRH), characterized by diffuse hepatic micronodular transformation in groups without fibrous septa between the nodules, is a rare benign liver lesion that has many synonyms in previous literature. Pathologic evaluation is the mainstay of accurate diagnosis. Treatment is focused on its underlying conditions and complications of portal hypertension. A 39-year-old man visited our hospital due to right upper quadrant pain and a palpable liver mass. Magnetic resonance examination revealed a slightly hyperintense tumor on T2-weighted images, and focal nodular hyperplasia was diagnosed by the radiologists. Atypical radiologic findings could not yield an accurate diagnosis. Surgical intervention was therefore performed. Pathologic examination of the resected liver tumor confirmed the diagnosis of NRH. We conclude that NRH should be included in the differential diagnosis of benign liver tumor.

Antiretroviral-Associated Portal Hypertension: A New Clinical Condition? Prevalence, Predictors and Outcome

Background

Cases of severe unexplained liver disease in HIV-infected individuals have recently been reported and are often associated with exposure to didanosine (ddI) and nodular regenerative hyperplasia. Herein, we examine the clinical outcome following ddI removal.

Methods

From 3,300 HIV-infected patients attending three clinics since 2004, all who exhibited persistently elevated aminotransferases and/or significant liver fibrosis in the absence of any known cause of liver damage were identified.

Results

Thirty-two individuals (prevalence ∼1%) met the inclusion criteria - all were on antiretroviral therapy. Of these, 84% were male and 68% had acquired HIV through homosexual contact. Liver biopsy was performed in 12, of whom three showed nonspecific advanced liver fibrosis, two nodular regenerative hyperplasia and three showed only periportal fibrosis. On follow up, nine patients developed episodes of hepatic decompensation, mainly as a consequence of portal hypertension; in eight cases (25%) portal thrombosis was diagnosed. No association was found with plasma HIV RNA or CD4+ T-cell count. All patients but three had been exposed to ddI for a median of 44 months; removal of ddI in 27 was followed 12 months later by improvement in clinical and laboratory parameters in 13 (48%) patients. Finally, a trend towards liver fibrosis improvement was recognised using FibroScan®.

Conclusions

Idiopathic persistent liver enzyme elevations in HIV-infected individuals are often associated with cirrhotic and non-cirrhotic portal hypertension. Although this is a relatively rare condition, prolonged exposure to ddI seems to play a pathogenic role and removal of the drug is associated with clinical and laboratory improvements.

Hepatoportal sclerosis as a cause of noncirrhotic portal hypertension in patients with HIV

BACKGROUND

Hepatoportal sclerosis (HPS) is a cause of noncirrhotic portal hypertension, with patients typically presenting with variceal bleeding. It is idiopathic in nature but is felt to be due to an abnormality of the intrahepatic vasculature. HPS is characterized by varying degrees of portal fibrosis, sclerosis of portal vein branches and dilatation of sinusoidal spaces. Nodular regenerative hyperplasia (NRH), another cause of noncirrhotic portal hypertension, has also been recently described in HIV patients initially diagnosed as having cryptogenic liver disease.

METHODS/RESULTS

We describe four cases of HIV+ patients presenting with noncirrhotic portal hypertension; liver biopsies were reviewed by an experienced liver pathologist and found to be consistent with HPS. No other etiologies for their liver disease were found.

CONCLUSIONS

HPS has been recently identified as a cause of noncirrhotic portal hypertension in patients with HIV. It should be considered in the differential diagnosis of HIV patients presenting with variceal bleeding. We postulate that it may be due to intrahepatic microthrombosis or an altered hepatic fibrogenesis related to highly active antiretroviral therapy or due to HIV itself.