Nodular regenerative hyperplasia of the liver and the Budd-Chiari syndrome. Case report, review of the literature and reappraisal of pathogenesis

Focal Liver Lesions in Budd-Chiari Syndrome: Spectrum of Imaging Findings

Budd-Chiari syndrome (BCS) is a rare clinical entity characterized by hepatic venous outflow obstruction, resulting in liver congestion and subsequent chronic parenchymal damage. This condition often leads to the development of focal liver lesions, including benign focal nodular hyperplasia-like regenerative nodules, hepatocellular carcinoma, and perfusion-related pseudo-lesions. Computed tomography, ultrasound, and magnetic resonance are the commonly employed imaging modalities for the follow-up of BCS patients and for the detection and characterization of new-onset lesions. The accurate differentiation between benign and malignant nodules is crucial for optimal patient management and treatment planning. However, it can be challenging due to the variable and overlapping characteristics observed. This review aims to provide a comprehensive overview of the imaging features and differential diagnosis of focal liver lesions in BCS, emphasizing the key findings and discussing the challenges associated with their interpretation, with the purpose of facilitating the subsequent clinical decision-making.

Budd-Chiari syndrome: consensus guidance of the Asian Pacific Association for the study of the liver (APASL)

Budd Chiari syndrome (BCS) is a diverse disease with regard to the site of obstruction, the predisposing thrombophilic disorders and clinical presentation across the Asia-Pacific region. The hepatic vein ostial stenosis and short segment thrombosis are common in some parts of Asia-Pacific region, while membranous obstruction of the vena cava is common in some and complete thrombosis of hepatic veins in others. Prevalence of myeloproliferative neoplasms and other thrombophilic disorders in BCS varies from region to region and with different sites of obstruction. This heterogeneity also raises several issues and dilemmas in evaluation and approach to management of a patient with BCS. The opportunity to recanalize hepatic vein in patients with hepatic vein ostial stenosis or inferior vena cava stenting or pasty among those membranous obstruction of the vena cava is a unique opportunity in the Asia-Pacific region to restore hepatic outflow closely mimicking physiology. In order to address these issues arising out of the diversity as well as the unique features in the region, the Asia Pacific Association for Study of Liver has formulated these guidelines for clinicians.

Budd-Chiari Syndrome: An Uncommon Cause of Chronic Liver Disease that Cannot Be Missed

Budd-Chiari syndrome (BCS), or hepatic venous outflow obstruction, is a rare cause of liver disease that should not be missed. Variable clinical presentation among patients with BCS necessitates a high index of suspicion to avoid missing this life-threatening diagnosis. BCS is characterized as primary or secondary, depending on etiology of venous obstruction. Most patients with primary BCS have several contributing risk factors leading to a prothrombotic state. A multidisciplinary stepwise approach is integral in treating BCS. Lifelong anticoagulation is recommended. Long-term monitoring of patients for development of cirrhosis, complications of portal hypertension, hepatocellular carcinoma, and progression of underlying diseases is important.

Budd-Chiari Syndrome in a Patient With Simultaneous Diagnosis of Hepatic Sarcoidosis and Nodular Regenerative Hyperplasia

Budd-Chiari syndrome (BCS) is a rare vascular disorder characterized by an obstruction of the hepatic venous outflow. Nodular regenerative hyperplasia (NRH) may develop as a result of an underlying autoimmune disease such as hepatic sarcoidosis. Only a few case reports have described cases with either NRH or hepatic sarcoidosis associated with BCS. We present a 42-year-old man presenting with BCS and signs of portal hypertension who was found to have an underlying pathological diagnosis of both hepatic sarcoidosis and NRH and who was successfully treated with a transjugular intrahepatic portosystemic shunt.

Budd-Chiari Syndrome and hepatic regenerative nodules: Magnetic resonance findings with emphasis of hepatobiliary phase

Budd-Chiari syndrome (BCS) is a disorder with numerous causes that is a result of hepatic outflow obstruction, in the absence of right heart failure or constrictive pericarditis. Acute Budd-Chiari syndrome is uncommon and clinically characterized by ascites, hepatomegaly, and hepatic insufficiency. In the majority of cases, patients present with chronic BCS, showing a dysmorphic liver disease with variable fibrosis deposition. In chronic Budd-Chiari syndrome, hepatocellular carcinoma (HCC) and benign regenerative nodules (called large regenerative nodules or FNH-like lesions) have been described in the literature. Very few studies have reported magnetic resonance imaging (MRI) findings about these nodules, using hepatobiliary contrast medium. The aim of our review is to describe the magnetic resonance imaging findings of hepatic regenerative nodules in BCS, with emphasis on the hepatobiliary phase, and to compare the imaging features of benign nodules with those of HCC.

Diagnosis of Budd-Chiari syndrome

Budd-Chiari syndrome (BCS) is defined by clinical and laboratory signs associated with partial or complete impairment of hepatic venous drainage in the absence of right heart failure or constrictive pericarditis. Primary BCS is the most frequent type and is a complication of hypercoagulable states, in particular myeloproliferative neoplasms. Secondary BCS involves tumor invasion or extrinsic compression. Most patients present with chronic BCS including a non-cirrhotic, dysmorphic, chronic liver disease with various degrees of fibrosis deposition. Acute BCS is rare, and patients present with hepatomegaly, ascites, and hepatic insufficiency. The diagnosis is based on imaging. Imaging features include (1) direct signs, in particular occlusion or compression of the hepatic veins and/or the inferior vena cava and venous collaterals and (2) indirect signs, in particular morphological changes in the liver with hypertrophy of the caudate lobe and delayed nodule formation. Ultrasound and magnetic resonance imaging are the gold standard for diagnosis. The aim of this review is to provide an overview of the role of imaging in the diagnosis of BCS.

Budd-Chiari syndrome: imaging review

Budd-Chiari syndrome (BCS), also known as hepatic venous outflow tract obstruction includes a group of conditions characterized by obstruction to the outflow of blood from the liver secondary to involvement of one or more hepatic veins (HVs), inferior vena cava (IVC) or the right atrium. There are a number of conditions that lead to BCS-ranging from hypercoagulable states to malignancies. In up to 25% patients, no underlying disorder is identified. Diagnosis of BCS is based on a combination of clinical and imaging features. A major part of the literature in BCS has been devoted to interventions; however, a detailed description of various imaging manifestations of BCS is lacking. In this review, we highlight the importance of various imaging modalities in the diagnosis of BCS.

Budd-Chiari syndrome: an update on imaging features

Budd-Chiari syndrome (BCS) is a rare cause of portal hypertension and liver failure. This condition is characterized by an impaired hepatic venous drainage. The diagnosis of BCS is based on imaging, which helps initiate treatment. Imaging findings can be categorized into direct and indirect signs. Direct signs are the hallmarks of BCS and consist of visualization of obstructive lesions of the hepatic veins or the upper portion of the inferior vena cava. Indirect signs, which are secondary to venous obstruction, correspond to intra- and extrahepatic collateral circulation, perfusion abnormalities, dysmorphy and signs of portal hypertension.

Multiple hyperplastic nodular lesions of the liver in the Budd-Chari syndrome: a case report and review of published reports

The Budd-Chari syndrome (BCS) is a group of disorders of hepatic vein outflow at various levels from the hepatic veins to inferior vena cave. We describe a 49-year-old man with multiple intrahepatic lesions who had been diagnosed with the BCS. The inferior vena cavography showed hepatic vein occlusion and long-range obstruction of inferior vena cava. The biopsy proved to be hyperplastic nodules, also called large regenerative nodules (LRNs). Both benign regenerative nodules and hepatocellular carcinoma (HCC) appear in patients with BCC; however, published reports about the diagnosis and differential diagnosis are limited. The incidence of HCC in patients with BCS varies greatly depending on geography. This case illustrates that benign nodules can arise in BCS patients. We reviewed published reports and speculated that medical procedures leading to portal perfusion decrease may be associated with the development of these hyperplastic nodules.

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.

Hepatocellular carcinoma: epidemiology, surveillance, and diagnosis

Hepatocellular carcinoma (HCC) is increasing in incidence in many countries, and is the most common cause of death in patients with cirrhosis. With regular surveillance, small early HCC lesions can be identified. An algorithm has been developed that allows for diagnosis of these lesions. Very early HCC lesions have high cure rates with appropriate treatment. If all these factors are in place most HCCs can be cured.

Acute deterioration of idiopathic portal hypertension requiring living donor liver transplantation: a case report

Case reports of severe idiopathic portal hypertension (IPH) requiring liver transplantation are very rare. We report the case of a 65-year-old woman who was diagnosed as having IPH. At the age of 60 years, her initial symptom was hematemesis, due to ruptured esophageal varices. Computed tomography of the abdomen showed splenomegaly and a small amount of ascites, without liver cirrhosis. She was diagnosed as having IPH and followed-up as an outpatient. Five years later, she developed symptoms of a common cold and rapidly progressive abdominal distension. She was found to have severe liver atrophy, liver dysfunction, and massive ascites. Living donor liver transplantation was then performed, and her postoperative course was uneventful. Histopathological findings of the explanted liver showed collapse and stenosis of the peripheral portal vein. The areas of liver parenchyma were narrow, while the portal tracts and central veins were approximate one another, leading to a diagnosis of IPH. There was no liver cirrhosis. The natural history of refractory IPH could be observed in this case. Patients with end-stage liver failure due to severe IPH can be treated by liver transplantation.

Regenerative nodules in patients with chronic Budd-Chiari syndrome: a longitudinal study using multiphase contrast-enhanced multidetector CT

OBJECTIVE

Our aim was to evaluate the serial evolution of regenerative nodules in patients with Budd-Chiari syndrome (BCS) treated with portal-systemic shunts, using multiphasic multidetector computed tomography (MDCT).

MATERIALS AND METHODS

Five patients each underwent three MDCT exams over an extended period ranging from 36 to 42 months. Two radiologists in consensus retrospectively reviewed each exam for each patient. Individual nodules were grouped according to size (size I: nodules with diameter < or =15 mm; size II: >15 mm but <30 mm; size III: > or =30 mm), pattern of enhancement (A: homogeneously hypervascular or B: with central scar), and segmental location. Four nodules classified as size II, which increased in size over time, were needle-biopsied.

RESULTS

We detected 61 nodules at the first exam, 66 nodules at the second exam (7 nodules disappeared and 12 new nodules), and 85 nodules at the third exam (8 disappeared and 27 new) for a total of 212 findings. Nodules were mostly found in the right hepatic lobe. Fourteen of the 15 nodules that disappeared over time were size I and enhancement pattern A. At unenhanced MDCT, 204 (96%) of the 212 findings were isodense. Overall, 100 nodules, including the 61 initially detected, were considered newly diagnosed; of these 84 (84%) were size I and pattern A. Of 57 nodules considered size I and pattern A at the first or second exam, 24 (42%) changed to pattern B at the third exam and either size II (n=18) or III (n=6). The four biopsied nodules were each confirmed as benign regenerative nodule. No patient developed HCC at 5-year follow-up period.

CONCLUSION

Hepatic nodules in BCS patients not only increase in number over time but may also increase in size and develop a central scar.

Significance of nodular regenerative hyperplasia occurring de novo following liver transplantation

Nodular regenerative hyperplasia (NRH) of the liver usually occurs in patients with rheumatological and myelolymphoproliferative disorders; the occurrence post-liver transplantation (LT) has traditionally been ascribed to the use of azathioprine. We report the clinical, biochemical, and radiological features of 14 patients who developed NRH, unrelated to azathioprine in most cases, 3 months to 11 yr after orthotopic LT. A total of 10 patients developed NRH within 4 yr (early onset), and 4 other patients developed the condition beyond 4 yr of LT (late onset). A total of 7 symptomatic patients, all in the early group, had features of portal hypertension with vascular abnormalities on Doppler ultrasonography that were preceded by the diagnosis of NRH. All asymptomatic patients, including each of the 4 patients in the late group, had normal hepatic ultrasound (US) studies. Two symptomatic patients had normalization of histologic abnormalities after correction of vascular abnormalities. In conclusion, observation is appropriate for patients who develop NRH late following LT. Patients in whom NRH is detected on liver biopsy early after transplantation are likely to develop portal hypertension in the future. Intervention aimed at correcting the vascular abnormalities in these patients may result in clinical as well as hepatic histological improvement.

Optimizing diagnosis from the medical liver biopsy

The histologic assessment of acute and chronic liver disease is based on an accurate description of the pattern of injury within the tissue specimen. Interpretation of the injury pattern requires review of the associated clinical and laboratory features. The morphologic interpretation achieves relevance only if it satisfactorily explains the clinical syndrome. Clinical characterization of the liver disease as having a hepatitic or cholestatic nature is useful in focusing the histologic assessment. The principal histologic patterns have hepatitic, steatotic, biliary, granulomatous, vascular, and metabolic designations, and mixed clinical and histologic patterns are possible. The goal of this review is to optimize the yield from the liver biopsy examination by indicating the importance of a systematic analysis of the tissue specimen and the crucial need for correlating the clinical and histologic patterns of liver injury. Meaningful histologic interpretations reflect the collaborative effort of the pathologist and the clinical physician. Neoplastic changes typically are cytologic transformations rather than injury patterns, and they are not discussed here.

Leberparenchymknoten bei pathologischer hepatischer Vaskularisation/Perfusion

Nodular regenerative hyperplasia (NRH) is characterized by a non-cirrhotic micronodular transformation of the liver parenchyma. It is based on the obliteration of small portal veins. Macroregenerative nodules (MRN) develop in areas of favourable blood flow in otherwise hypoperfused liver tissue. Hypoperfusion is caused by obliteration of liver veins and/or large portal veins with the subsequent atrophy or extinction of parenchyma. The hyperperfused and sometimes rapidly growing MRN might simulate a malignant tumor in CT and MRT. Morphologically, MRN resemble FNH. In contrast to hepatocellular adenoma, they show a more or less nodular architecture with fibrous septa and ductular structures. NRH and cases of MRN without cirrhosis can indicate an extrahepatic/systemic disease causing altered liver perfusion. MRN in liver cirrhosis must be differentiated from dysplastic nodules and highly differentiated hepatocellular carcinoma by cytological and microarchitectural criteria. Focal nodular hyperplasia (FNH) can imitate liver cirrhosis, steatohepatitis, cholangitis or chronic hepatitis, if biopsy material does not include normal perilesional liver tissue. Telangiectatic FNH might resemble classic hepatocellular adenoma. Neoductular structures and septation argue for this rare subtype of FNH. Neoductular transformation of hypoperfused liver parenchyma might imitate cholangioma or cholangiocarcinoma.

Portal vein thrombosis during antineoplastic chemotherapy in children: Report of five cases and review of the literature

We report five paediatric cases of portal vein thrombosis (PVT) occurring during chemotherapy, observed in two institutions over an 8-year time period. These children aged 2.5-15 years were treated for Burkitt's lymphoma, Ewing's tumour, small cell bone tumour or medulloblastoma. PVT was diagnosed on colour Doppler ultrasonography (US). In four patients, thrombosis occurred 2-45 days after severe hepatic veno-occlusive disease (HVOD) secondary to intensive chemotherapy containing busulfan. In one case, PVT occurred in the absence of HVOD in a patient with pre-existing periportal lymphomatous infiltration. Four patients experienced persistent portal hypertension, which resulted in death in one. PVT during chemotherapy in children is a rare event and appears to be closely related to intensive chemotherapy containing busulfan and to be associated with HVOD.

Focal hyperplastic hepatocellular nodules in hepatic venous outflow obstruction: a clinicopathological study of four patients and 24 nodules

AIMS

In hepatic venous outflow obstruction (Budd-Chiari syndrome), focal hepatocellular nodules are occasionally discovered showing variable morphology. These could be interpreted either as neoplastic (adenoma), regenerative (large regenerative nodule) or reactive to abnormal vasculature (focal nodular hyperplasia). The aim of this study was to investigate their histogenesis and to determine their morphological characteristics in order to provide diagnostic criteria.

MATERIAL AND METHODS

Twenty-four hepatocellular nodules were studied, which were found in three explanted livers and in one additional autopsied liver from four patients with Budd-Chiari syndrome. As controls, we employed three explanted livers without nodules from patients who also suffered from Budd-Chiari syndrome. We attempted to classify the nodules morphologically as either adenoma-like, large regenerative nodule or focal nodular hyperplasia-like, using criteria from the literature.

RESULTS

Out of the four cases, we observed two nodules in each of two livers, five in the third one and up to 15 in the remaining one. The size of the nodules ranged from 4 to 25 mm. Eleven nodules could be categorized as large regenerative nodules (two of them with a central scar), seven as focal nodular hyperplasia-like and six as adenoma-like. Some large regenerative nodules showed proliferated arteries with muscular hyperplasia similar to that seen in focal nodular hyperplasia. In the individual livers we could find nodules of various categories. Patchy or diffuse monoacinar regeneration was seen in most cases (six out of seven cases) in the macroscopically non-nodular liver parenchyma. In addition, thrombotic obstruction of portal vein branches was present in all except one of the nodular cases, but in none of the controls. Thus, it appears that portal venous obstructions are frequently, but not invariably associated with the development of nodules.

CONCLUSIONS

The hepatocellular nodules seen in livers from patients with Budd-Chiari syndrome share morphological characteristics with large regenerative nodules, focal nodular hyperplasia and hepatocellular adenomas. Their multiplicity, the existence of mixed lesions, the frequent hepatocellular regenerative background as well as the frequently associated portal venous obstructions suggest that these nodules are regenerative in nature and conditioned by an uneven blood perfusion throughout the liver. In their differential diagnosis, the clinicopathological context in which they occur is of paramount importance and should allow recognition that those resembling adenomas may not be true neoplasms.

Hepatic focal nodular hyperplasia in children previously treated for a solid tumor. Incidence, risk factors, and outcome

BACKGROUND

The detection of hepatic nodules, particularly in patients treated for a previous malignancy, raises a diagnostic dilemma. Focal nodular hyperplasia (FNH) of the liver is an uncommon, benign tumor in children and must be differentiated from malignant hepatic lesions. The etiology of FNH is obscure, and its pathogenesis is poorly understood. FNH may be a reaction to localized vascular abnormalities and circulatory disturbances. The goal of the current study was to identify risk factors for the occurrence of FNH in children who had received prior treatment for a malignant tumor.

METHODS

The current retrospective study examined 14 cases of FNH in pediatric patients who previously had been treated for a malignancy. Diagnosis was based on clinical and radiologic findings and was proven histologically in four cases.

RESULTS

FNH lesions were discovered by chance during routine examination in 78% of patients. The incidence of FNH was particularly high in the current series (0.45%) compared with the incidence in the general pediatric population. High doses of alkylating agents (e.g., busulfan or melphalan), venoocclusive disease, and liver radiotherapy may be responsible for injury to the vascular endothelium and subsequent localized circulatory disturbances. FNH is characterized by the absence of complications after its detection; therefore, only close follow-up is recommended.

CONCLUSIONS

FNH appears to be a late complication of an iatrogenic vascular disease in children with a history of malignancy.

Arterial and portal circulation and parenchymal changes in Budd-Chiari syndrome: a study in 17 explanted livers

Hepatic parenchymal changes associated with Budd-Chiari syndrome (BCS) have been tentatively explained by combined arterial and portal perfusion disturbances in addition to the complete occlusion of hepatic veins. The aim of this study was to correlate pretransplant course and vascular imaging with pathologic findings in livers explanted for BCS. Seventeen consecutive white patients who underwent transplantation for severe classic BCS were retrospectively analyzed. Pretransplant course was 1 year or less in 8 patients and more than 1 year in 9 patients. Thrombophilia was found in 16 patients (94%). Imaging showed decreased portal perfusion in 16 patients (94%) and increased arterial perfusion in 9 patients. Histology showed obstructive portal venopathy and nodular regenerative hyperplasia (NRH) aspects in all cases, large regenerative nodules resembling focal nodular hyperplasia (FNH) in 9 cases, and cirrhosis in 2 cases. Patients with increased arterial inflow had large regenerative nodules and a protracted pretransplant course. Patients with acute thrombi in portal veins had parenchymal infarcts (2 cases) and a short pretransplant course. In conclusion, patients with severe BCS have a constant impaired perfusion inflow unrelated to progression of cirrhosis but related to the outcome. An early decrease in portal perfusion is observed in the short term and is responsible for NRH or infarcts if complicated with large thrombi. An increase in arterial perfusion compensates impaired portal flow in chronic BCS. Arterial hyperemia contributes to the development of large regenerative nodules that are FNH-like. This pathologic situation offers an interesting vascular model to further understand the parenchymal response to changes in hepatic blood flow.

Focal nodular hyperplasia-like areas in cirrhosis

AIMS

Focal nodular hyperplasia-like lesions have rarely been described in cirrhotic livers. We describe five cases of such lesions.

METHODS AND RESULTS

Between 1998 and 2001, 146 liver transplants were performed at the Royal Free Hospital for cirrhosis of the liver. Nodular lesions identified in the livers removed at transplantation were defined histologically according to the International Working Party classification (Hepatology 1995; 22; 983). They were present in 63 of these livers, as follows: 36 dysplastic nodules, 121 macroregenerative nodules, and 71 hepatocellular carcinomas. In five patients, an additional 12 nodules (size range 4-23 mm, median 10.5 mm) showed histological features suggestive of focal nodular hyperplasia including mildly inflamed vascular fibrous septa, and ductular proliferation. Pre-transplantation imaging showed features suspicious for hepatocellular carcinoma, in three of these lesions (12, 23 and 23 mm diameter) from two different patients. These lesions were histologically indistinguishable from focal nodular hyperplasia occurring in non-cirrhotic livers, with fibrous scars and septa which contained vascular and ductular structures.

CONCLUSIONS

It is important to recognize that these lesions may occur in the context of cirrhosis and that they should be considered in the differential diagnosis with hepatocellular carcinoma, dysplastic nodules and macroregenerative nodules.

Benign regenerative nodules in Budd-Chiari syndrome and other vascular disorders of the liver: radiologic-pathologic and clinical correlation

Large regenerative nodules are benign liver lesions that are frequently seen in Budd-Chiari syndrome and less commonly in other vascular disorders of the liver or systemic conditions such as autoimmune disease, myeloproliferative disorders, and lymphoproliferative disorders. They are usually multiple, with a typical diameter of 0.5-4 cm. At pathologic analysis, large regenerative nodules are well-circumscribed, round lesions that may distort the contour of the liver. Only a minority of these nodules are detected at cross-sectional imaging. At multiphasic helical computed tomography, large regenerative nodules are markedly and homogeneously hyperattenuating on arterial dominant phase images and remain slightly hyperattenuating on portal venous phase images. Large regenerative nodules are bright on T1-weighted magnetic resonance images and show the same enhancement characteristics after intravenous bolus administration of gadolinium contrast material. They are predominantly isointense or hypointense relative to the liver on T2-weighted images. There is no evidence that large regenerative nodules degenerate into malignancy. If these nodules are misdiagnosed as multifocal hepatocellular carcinoma, patients might be denied transplantation or offered inappropriately aggressive therapy such as transcatheter arterial chemoembolization. Understanding the clinical setting and imaging appearance of large regenerative nodules can help avoid misdiagnosis as other hypervascular masses.

Benign hepatic nodules in Budd-Chiari syndrome: radiologic-pathologic correlation with emphasis on the central scar

OBJECTIVE

The purpose of this study was to determine the imaging features of benign hepatic nodules in patients with Budd-Chiari syndrome and to correlate them with pathologic findings, with special attention placed on the presence of a central scar.

MATERIALS AND METHODS

Imaging findings of 59 benign hepatic nodules in four patients with chronic Budd-Chiari syndrome were analyzed retrospectively, and radiologic- pathologic correlation was performed in three patients with 50 hepatic nodules who underwent liver transplantation. All patients underwent multiphasic helical CT. In three patients with 29 lesions, MR imaging, including a multiphasic dynamic study, was performed. The CT and MR imaging findings in these patients were compared with those of 103 small hepatocellular carcinomas in 56 other patients (54 of them displayed chronic hepatitis or liver cirrhosis associated with viral hepatitis but none had Budd-Chiari syndrome). Image analysis was performed by two radiologists with no knowledge of the diagnosis.

RESULTS

All patients with Budd-Chiari syndrome exhibited multiple benign nodules up to 3 cm in diameter, and 42 of 59 lesions were hypervascular. Microscopically, 15 of 32 nodules demonstrated a central scar; moreover, some nodules closely resembled focal nodular hyperplasia. Frequencies of hyperintensity on T1-weighted images (14/29 vs 25/103), hypointensity on T2-weighted images (7/29 vs 1/103), and the presence of a central scar (6/59 vs 1/103) were significantly higher in benign nodules than in hepatocellular carcinomas (p < 0.05; Fisher's exact test). Moreover, for lesions larger than 1 cm, imaging studies revealed a central scar in six of 15 benign lesions.

CONCLUSION

Benign hepatic nodules in patients with in Budd-Chiari syndrome are usually small, multiple, and hypervascular. The presence of a central scar is a characteristic feature in those larger than 1 cm in diameter.

Benign focal lesions of the liver

This article focuses on the origin, diagnosis, and management of focal benign lesions of the liver. The most common lesions include cavernous hemangioma, focal nodular hyperplasia, hepatic adenoma, and nodular regenerative hyperplasia. A number of less frequent occurring lesions are also discussed. In general, the common lesions can be diagnosed by radiologic imaging, but occasionally biopsies are required, and surgical removal is often needed.

Hepatic nodules in Budd-Chiari syndrome: imaging features

PURPOSE

To analyze the imaging features of nodules associated with Budd-Chiari syndrome.

MATERIALS AND METHODS

The authors retrospectively studied images obtained in 23 patients with liver nodules who were being followed up for Budd-Chiari syndrome. Doppler ultrasonography was performed in all patients, computed tomography in 16, and magnetic resonance (MR) imaging in 20. The following lesion features were evaluated: location, number, size, vascularization, qualitative signal intensity at MR imaging, and homogeneity. Nodules were diagnosed on the basis of histopathologic findings or clinical and biologic data with no change at imaging during 2-year follow-up.

RESULTS

All patients had histopathologic features of chronic Budd-Chiari syndrome. Four patients had hepatocellular carcinoma (HCC), with one to three lesions. The mean diameter of the largest HCC lesion in each patient was 7.3 cm. All HCC lesions were heterogeneous and had high signal intensity on T2-weighted MR images. Nineteen patients had multiple benign regenerative nodules, most of which were smaller than 4 cm. Most nodules were homogeneous and hyperintense on T1- and T2-weighted images. In 15 patients, nodules were hypervascular in the arterial phase.

CONCLUSION

In patients with chronic Budd-Chiari syndrome, multiple (> 10) small (< 4-cm) lesions are suggestive of benignity.

Pathology of the liver in Budd-Chiari syndrome: portal vein thrombosis and the histogenesis of veno-centric cirrhosis, veno-portal cirrhosis, and large regenerative nodules

Hepatic vein (HV) thrombosis causes ascites, hepatomegaly, and severe congestion of the liver (Budd-Chiari syndrome [BCS]). Severe hepatic fibrosis develops in this syndrome with a variety of histological patterns. Some livers have a pattern of cirrhosis in which there is fibrous bridging between HVs and portal tracts (veno-portal cirrhosis). Other livers have a pattern of "reversed-lobulation cirrhosis" (veno-centric cirrhosis), in which fibrous bridging between HVs and portal tracts is minimal. The prevalence and pathogenesis of these forms of cirrhosis and the effect of portal vein (PV) thrombosis in this disease have not been studied. We examined 15 resected livers from patients with BCS to determine the distribution of vascular obstruction and the character of the parenchymal response. Six livers had veno-portal cirrhosis, and all of these had severe PV obliteration caused by thrombosis. Three livers had veno-centric cirrhosis and had normal medium and large PVs. The remaining six livers had mixed veno-centric/veno-portal cirrhosis and had moderate PV obliteration. The nodules in veno-centric cirrhosis had evidence of an unusual circulation with small arteries supplying a midzonal venous plexus that appeared to drain retrogradely into patent small PVs. Nine livers had large regenerative nodules histologically similar to focal nodular hyperplasia. PV thrombosis is a frequent occurrence in BCS. The correlation between PV thrombosis and the pattern of cirrhosis suggests a role for PV obliteration in the genesis of veno-portal bridging fibrosis in this disease and possibly in other diseases leading to cirrhosis.

MR imaging of hepatic nodular regenerative hyperplasia

Nodular regenerative hyperplasia (NRH), a rare condition that is commonly associated with noncirrhotic portal hypertension, is not well described in the MR literature. Three patients at two institutions were identified who had both abdominal MR imaging and pathologic evidence of NRH. All examinations were performed at 1.5 T and included axial T1- and T2-weighted spin-echo (SE) images. The MR studies were reviewed by two radiologists in consensus. Two patients had multiple liver lesions that had high signal components on T1-weighted images and were predominantly isointense with liver on the T2-weighted images. One patient had no focal lesions identified. NRH, when visualized on MR images, appears as multifocal masses with shortened T1 and T2 similar to liver. NRH should be considered in the differential diagnosis of hepatocellular tumors, especially in patients with a predisposing condition.

Budd-Chiari syndrome

Budd-Chiari syndrome is the generic term for different forms of hepatic venous outflow obstruction resulting in a clinical picture of portal hypertension and hepatomegaly. Three levels of venous outflow obstruction may be recognized, affecting respectively the small intrahepatic (IVC). Each level of obstruction is related to a different aetiology. Clinical manifestations range from mild symptoms to acute or chronic end-stage liver disease. Treatment is surgical in the great majority of patients. Occlusion of the IVC may be treated by removal of the caval obstruction in selected patients. Hepatic outflow obstruction may be circumvented by different forms of shunting from the portal or upper mesenteric vein to the IVC or right atrium, depending on the level of obstruction and the difference in venous pressure. For the rare patient presenting with acute or chronic end-stage liver failure, hepatic transplantation may be a life-saving procedure.

Laparoscopic study of peliosis hepatis and nodular transformation of the liver before and after renal transplantation: natural history and aetiology in follow-up cases

Although peliosis hepatis and nodular transformation of the liver can occur after renal transplantation, their prevalence has not been well defined. To investigate the incidence of these complications, 137 laparoscopies were studied, 52 in 50 cases before and 85 in 66 cases after renal transplantation. To elucidate the aetiology and natural history of these diseases, cases were followed up by repeated laparoscopies. Peliosis was observed after transplantation (before: n = 1, after: n = 15 [22%], p < 0.005). Nodular transformation was seen only after transplantation (n = 5 [7%]), and was accompanied by peliosis (n = 4, p < 0.01). On observation before and after transplantation in the same cases, these diseases appeared after transplantation (peliosis: n = 9, p < 0.005; nodular transformation: n = 2). In follow-up cases, these diseases were confirmed after the discontinuation of or the controlled administration of immunosuppressants. The aetiology of the micronodular transformation which appeared following peliosis in a case treated without cyclosporin was shown to be azathioprine. However, the macronodular transformation observed in two cases treated with both azathioprine and cyclosporin seemed to be due to cyclosporin. This suggests that cases of peliosis hepatis and nodular transformation which appear after renal transplantation are associated with immunosuppressants, and that cyclosporin treatment may also affect the morphogenesis of nodular transformation.

Nodular transformation of the liver associated with portal and pulmonary arterial hypertension

A case of multiple focal nodular hyperplasia (FNH) of the liver associated with noncirrhotic portal hypertension and later complicated by pulmonary arterial hypertension leading to death from right heart failure is reported. In retrospect, the portal hypertension diagnosed in early life was most likely due to a congenital hypoplasia of portal vein branches and multiple FNH, a hyperplastic response of the liver parenchyma in association with anomalies of hepatic arterial branches as found within the lesions. This case may represent a form of multiple FNH syndrome restricted to the liver, because neither extrahepatic vascular malformation nor brain tumor was identified at autopsy. The FNH lesions had considerably expanded over the years, and the severe sinusoidal congestion due to chronic right-sided heart failure with subsequent prolonged parenchymal exposure to blood-borne hepatotrophic factors is a likely explanation for both the massive enlargement of FNH lesions and the nodular regenerative hyperplasia observed in the intervening parenchyma.

Nodular regenerative hyperplasia in the rat induced by a selenium-enriched diet: study of a model

Weaned male rats were fed a 4 ppm selenium diet. Compared after 2 mo with a control group fed a 0.4 ppm diet, the rats' body weights had not significantly decreased and liver function was normal, but portal pressure was 1.8 times higher (p less than 0.05). Liver weight was slightly increased (10.3%; p less than 0.05). All livers had an abnormal appearance. In the less severe cases the surface was only slightly irregular, but in the more severe cases, atrophic micronodular lobes and hypertrophic lobes, with mildly irregular surfaces, were present. On light microscopy, atrophic lobes displayed a peripheral nodular zone with micronodules separated by rows of atrophic hepatocytes without fibrosis, characteristic of nodular regenerative hyperplasia, and a central atrophic zone that was sometimes peliotic. Hypertrophic lobes and livers in the less severe cases had only minor and relatively localized evidence of nodular regenerative hyperplasia; occasional peliosis was seen. In all cases portal veins, hepatic veins and hepatic arteries were normal. By electron microscopy, in nonnodular zones with no obvious evidence of parenchymal atrophy, the endothelial wall showed signs of complete or incomplete capillarization with frequent enlargement of the Disse space. The selenium-enriched diet is a reproducible model of liver nodular regenerative hyperplasia. In this model, damage to the sinusoidal wall could represent the primum movens of microcirculatory disturbances.

Nodular regenerative hyperplasia of the liver associated with metastases of pancreatic endocrine tumour: report of two autopsy cases

Two autopsy cases with multiple hepatic metastases of pancreatic endocrine tumours and nodular regenerative hyperplasia of the liver (NRH) are reported. The tumour cells were positive for glucagon, insulin, gastrin and vasoactive intestinal polypeptide immunohistochemically and the serum gastrin was elevated in one case. In the other, tumour cells were positive for insulin. Controls failed to show NRH in the non-metastatic part of 35 autopsies of livers with multiple hepatic metastases. A combination of hepatotrophic hormonal factor(s) and disturbed hepatic circulation associated with hepatic metastases may be important in the development of NRH.