Etiological analysis of focal nodular hyperplasia of the liver, with emphasis on similar abnormal vasculatures to nodular regenerative hyperplasia and idiopathic portal hypertension

Giant focal nodular hyperplasia with a background of hepatic steatosis in a 14-year-old boy

Giant focal nodular hyperplasia (GFNH) is rarely seen in children, presenting complex diagnostic and management considerations. Pathognomonic radiographic findings can be absent in this population, and the nuances of pathologic examination are critical. We present a child with a GFNH involving the right side of the liver arising in the background of hepatic steatosis. The details of the diagnosis and therapeutic decisions involved in his treatment are discussed.

A case of inferior right hepatic vein-right hepatic vein bypass with interrupted inferior vena cava compressed by focal nodular hyperplasia in caudate lobe

Focal nodular hyperplasia (FNH) is a relatively common benign liver tumor with rare indications to surgery. Budd-Chiari syndrome is a rare condition caused by interrupted hepatic venous outflow in the hepatic veins and inferior vena cava (IVC). A 42-year-old woman was referred to our department with a hepatic tumor. Patient's chief complaint was leg edema. Because of this symptom, it was difficult for the patient to stand for more than 20 min in the evening. Computed tomography (CT) showed a hypervascular mass compressing IVC in the caudate lobe of the liver. Fine needle aspiration was performed, and preoperative diagnosis was focal nodular hyperplasia (FNH). Hepatic resection of the right caudate lobe was performed. Postoperative histological examination revealed that the tumor was FNH. After surgery, the patient's leg edema disappeared, and postoperative CT revealed that severe IVC stenosis was improved. Although there have been several reports of giant FNH causing Budd-Chiari syndrome, this case shows the stenosis of IVC below the root of hepatic veins causing Budd-Chiari-like syndrome without portal hypertension. The location of the tumor considerably attributed to the congestion of venous flow in IVC causing various symptoms and intrahepatic inferior right hepatic vein-right hepatic vein bypass. The surgical indication of FNH is limited in most cases; however, the current report alerts that the location of FNH should be taken into account when monitoring it.

Two cases of benign hepatic nodules caused by sinusoidal dilatation with different hemodynamics

We describe two cases of benign nodules caused by sinusoidal dilatation with different hemodynamic statuses. Case 1 was a 50-year-old woman with a 1-cm nodule that showed a low density in the arterial phase of computed tomography. Pathologically, there were no atypical cells with sinusoidal dilatation, and immunostaining was negative for CD34. We speculated that sinusoidal dilatation was caused by congestion due to loss of frequency of the central vein. In contrast, case 2 was a 50-year-old woman with a 1.5-cm nodule that was highly stained in the arterial phase of computed tomography. Although she had a sinusoidal dilatation similar to that in case 1, immunostaining was positive for CD34. Sinusoidal dilatation was thought to be caused by hyperperfusion of arterial blood. Moreover, CD34 may be potentially useful for the differentiation of the hemodynamic status.

Abernethy malformation associated with Caroli's syndrome in a patient with a PKHD1 mutation: a case report

Background

Abernethy malformation is a rare congenital anomaly characterised by the partial or complete absence of the portal vein and the subsequent development of an extrahepatic portosystemic shunt. Caroli’s disease is a rare congenital condition characterised by non-obstructive saccular intrahepatic bile duct dilation. Caroli’s disease combined with congenital hepatic fibrosis and/or renal cystic disease is referred to - Caroli’s syndrome. The combination of Abernethy malformation and Caroli’s syndrome has not been reported previously.

Case presentation

We present the case of a 23-year-old female who was found to have both type II Abernethy malformation and Caroli’s syndrome. Radiological imaging was performed, including computed tomography with three-dimensional reconstruction and magnetic resonance imaging with (magnetic resonance cholangiopancreatography (MRCP), which revealed a side-to-side portocaval shunt, intrahepatic bile duct dilation, congenital hepatic fibrosis, and renal cysts. In addition, PKHD1 (polycystic kidney and hepatic disease 1) gene mutational analysis revealed a paternally inherited heterozygous missense mutation (c.1877A > G, p.Lys626Arg). A liver biopsy confirmed the pathological features of Caroli’s syndrome.

Conclusions

To our knowledge, this is the first reported case of a patient with both type II Abernethy malformation and Caroli’s syndrome diagnosed using a comprehensive approach that included imaging, mutational analysis, and liver biopsy. Additionally, this is the second reported case to date of an Asian patient presenting with liver and renal disorders with the same paternally inherited PKHD1 missense mutation.

Focal nodular hyperplasia of the liver: an emerging complication of hematopoietic SCT in children

Hepatic focal nodular hyperplasia (FNH) is a nonmalignant condition rarely affecting children previously treated for cancer, especially those who received hematopoietic SCT (HSCT). Some aspects of its pathogenesis still remain unclear and a strong association with specific risk factors has not yet been identified. We report here a single institution's case series of 17 patients who underwent HSCT and were diagnosed with FNH, analyzing retrospectively their clinical features and the radiological appearance of their hepatic lesions. We aimed to compare the diagnostic accuracy of ultrasound (US) and magnetic resonance imaging (MRI) and to explore the role of transient elastography (FibroScan) to evaluate the degree of hepatic fibrosis in FNH patients. Our analysis showed an association of FNH with age at transplant ⩽12 years (hazard ratio (HR) 9.10); chronic GVHD (HR 2.99); hormone-replacement therapy (HR 4.02) and abdominal radiotherapy (HR 4.37). MRI proved to be a more accurate diagnostic tool compared with US. Nine out of 12 patients who underwent FibroScan showed hepatic fibrosis. Our study points out that FNH is an emerging complication of HSCT, which requires a lifelong surveillance to follow its course in cancer patients.

Development of nodular regenerative hyperplasia (NRH) with portal hypertension following the administration of oxaliplatin for the recurrence of colon cancer

Nodular regenerative hyperplasia (NRH) is associated with autoimmune and hematologic diseases and may lead to portal hypertension. We herein report a case of NRH diagnosed based on a liver biopsy. A 63-year-old woman developed esophageal varices and splenomegaly. She had undergone surgery for transverse colon cancer 24 years earlier and received systemic chemotherapy (FOLFOX4 including oxaliplatin) to treat lymph node metastasis 21 years after the operation. The present liver biopsy confirmed NRH, and, after two years, she received endoscopic injection sclerotherapy. Oxaliplatin was suspected to be the causative agent of NRH in this case. Therefore, physicians must consider the possibility of NRH in patients who receive chemotherapy.

Pathological diagnosis of benign hepatocellular nodular lesions based on the new World Health Organization classification

There are various types of benign hepatocellular nodular lesions, and their diagnostic criteria were formulated in detail. However, in 2010, the new World Health Organization (WHO) classification introduced immunohistochemical diagnostic criteria for hepatocellular adenoma (HCA) reflecting molecular pathological properties, and HCA was classified into 4 subtypes. These criteria were useful for its differential diagnosis from focal nodular hyperplasia (FNH). They were also useful for the diagnosis of HCA, its subtyping, and differentiation from FNH in Japan. However, the new WHO classification is based on principles that differ from those of conventional definitions of disease concepts and methods for the differential diagnosis. Therefore, it has caused disagreements in the diagnosis in some cases. Based on this background, we present a new perspective on the diagnosis of benign hepatocellular nodular lesions.

Focal nodular hyperplasia-like lesion of the liver with focal adenoma features associated with idiopathic portal hypertension

Great progress has been made in the diagnosis of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) in the last few years due to the use of molecular criteria. This has allowed us to identify a new type of hepatic nodule. In this case report, we present a male patient with a hepatic nodule associated with idiopathic portal hypertension (IPH) pathologically exhibiting not only the morphological features of FNH, such as ductular reactions, dilated sinusoids, major vascular abnormalities and an immunohistochemical "map-like" pattern of glutamine synthetase (GS), but also the immunohistological features of focal HCA, such as strong expression of serum amyloid A and C-reactive protein and weak expression of GS. As the final diagnosis, the nodule was identified as an FNH-like lesion with focal inflammatory hepatocellular adenoma.

Focal nodular hyperplasia: hepatobiliary enhancement patterns on gadoxetic-acid contrast-enhanced MRI

OBJECTIVES

To assess the range of hepatobiliary enhancement patterns of focal nodular hyperplasia (FNH) after gadoxetic-acid injection, and to correlate these patterns to specific histological features.

MATERIALS AND METHODS

FNH lesions, imaged with Gadoxetic-acid-enhanced MRI, with either typical imaging findings on T1, T2 and dynamic-enhanced sequences or histologically proven, were evaluated for hepatobiliary enhancement patterns and categorized as homogeneously hyperintense, inhomogeneously hyperintense, iso-intense, or hypo-intense-with-ring. Available histological specimens of FNHs (surgical resection or histological biopsy), were re-evaluated to correlate histological features with observed enhancement patterns.

RESULTS

26 FNHs in 20 patients were included; histology was available in six lesions (four resections, two biopsies). The following distribution of enhancement patterns was observed: 10/26 homogeneously hyperintense, 4/26 inhomogeneously hyperintense, 5/26 iso-intense, 6/26 hypointense-with-ring, and 1/26 hypointense, but without enhancing ring. The following histological features associated with gadoxetic-acid uptake were identified: number and type of bile-ducts (pre-existent bile-ducts, proliferation, and metaplasia), extent of fibrosis, the presence of inflammation and extent of vascular proliferation.

CONCLUSION

FNH lesions can be categorized into different hepatobiliary enhancement patterns on Gadoxetic-acid-enhanced MRI, which appear to be associated with histological differences in number and type of bile-ducts, and varying the presence of fibrous tissue, inflammation, and vascularization.

Current consensus and guidelines of contrast enhanced ultrasound for the characterization of focal liver lesions

The application of ultrasound contrast agents (UCAs) is considered essential when evaluating focal liver lesions (FLLs) using ultrasonography (US). Microbubble UCAs are easy to use and robust; their use poses no risk of nephrotoxicity and requires no ionizing radiation. The unique features of contrast enhanced US (CEUS) are not only noninvasiveness but also real-time assessing of liver perfusion throughout the vascular phases. The later feature has led to dramatic improvement in the diagnostic accuracy of US for detection and characterization of FLLs as well as the guidance to therapeutic procedures and evaluation of response to treatment. This article describes the current consensus and guidelines for the use of UCAs for the FLLs that are commonly encountered in US. After a brief description of the bases of different CEUS techniques, contrast-enhancement patterns of different types of benign and malignant FLLs and other clinical applications are described and discussed on the basis of our experience and the literature data.

Benign hepatic nodular lesions after treatment for childhood cancer

BACKGROUND

Benign nodular hepatic regenerating lesions such as focal nodular hyperplasia (FNH) have been reported as rare complications of the antineoplastic therapy received during infancy. Little is known about the risk factors associated with the onset of these lesions and their diagnostic management.

METHODS

We have analyzed a series of benign hepatic nodular lesions occurring in children previously treated for malignant tumors in our institution in a period of 11 years. An extensive description of the imaging presentation of the lesions has been provided to facilitate the differential diagnosis, and a risk factor analysis has been conducted.

RESULTS

A total of 14 diagnoses (10 FNH and 4 hemangiomas) of benign nodular hepatic lesions have been found. Hematopoietic stem cell transplantation is the most important statistically independent risk factor associated with the development of these lesions, especially for FNH. No malignant transformation of nodules has been recorded during a median follow-up time of 4 years.

CONCLUSIONS

In our experience, FNH is the most frequent benign nodular hepatic lesions occurring after treatment for childhood cancer. Hematopoietic stem cell transplantation is the most important risk factor to be taken in account. After a secure diagnosis of these benign lesions, only a close imaging follow-up is recommended.

Multiple hypervascular FNH-like lesions in a patient with no history of alcohol abuse or chronic liver disease

A 64-year-old Japanese woman with a history of bronchiectasis presented with multiple hypervascular nodules in both lobes of the liver without hepatitis B or C virus infection. Imaging studies, including ultrasound, contrast-enhanced computed tomography and magnetic resonance imaging, showed hypervascularity in the early phase. Histologically, no lipid degeneration was observed; however, there was a mild increase in cell density, miniaturization of nuclei, increased chromatin content, partial sinusoidal dilatation and congestion. No unpaired arteries were evident. The diagnosis based on the pathology and diagnostic radiology findings was multiple hypervascular focal nodular hyperplasia (FNH)-like lesions with no history of alcohol abuse or chronic liver disease.

Clonality and TP53 mutation analysis of focal nodular hyperplasia of the liver

Focal nodular hyperplasia (FNH) is considered a benign tumor of the liver. However, the biologic nature and clonality status of FNH are not well established. We sought to determine the clonality and TP53 mutation status of FNH to better characterize the nature of FNH. We analyzed 15 cases of FNH from female patients who underwent surgical resection of their lesions. Genomic DNA was extracted from paraffin-embedded tissue sections using laser-capture microdissection and analyzed for X-chromosome inactivation status and TP53 mutations by direct DNA sequencing. Thirteen cases were informative for X-chromosome inactivation analysis. Of the 13 informative cases, 4 (31%) showed a nonrandom pattern of X-chromosome inactivation, consistent with monoclonal origin. No TP53 mutations were detected in any of the FNH cases. The clonality status was not associated with any clinicopathologic parameters such as age and lesion size. Our data indicate that a significant proportion of FNH lesions have a monoclonal origin, suggesting that they are neoplastic rather than reactive.

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.

Radiological findings in a case of multiple focal nodular hyperplasia associated with portal vein atresia and portopulmonary hypertension

We present here the radiological findings of a rare case of multiple focal nodular hyperplasia that was associated with portal vein atresia and portopulmonary hypertension in a young woman. This case illustrates and supports the pathophysiological hypotheses that were previously proposed for the coexistence of these three abnormalities.

Coexistence of nodular regenerative hyperplasia of the liver and pulmonary arterial hypertension in patients with connective tissue diseases: report of three cases and review of the literature

Nodular regenerative hyperplasia of the liver (NRH) is known to be a rare condition in patients with connective tissue diseases (CTD). In this report, we document three patients with CTD who had both NRH and pulmonary hypertension (PH). All three patients developed PH during their course and thereafter developed NRH. The clinical course of these patients suggests that circulatory disturbance caused by PH might be a trigger for NRH.

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.

Liver cell adenoma: A case report with clonal analysis and literature review

We report a case of liver cell adenoma (LCA) in a 33-year-old female patient with special respect to its clonality status, pathogenic factors and differential diagnosis. The case was examined by histopathology, immunohistochemistry and a clonality assay based on X-chromosomal inactivation mosaicism in female somatic tissues and polymorphism at androgen receptor focus. The clinicopathological features of the reported cases from China and other countries were compared. The lesion was spherical, sizing 2 cm in its maximal dimension. Histologically, it was composed of cells arranged in cords, most of which were two-cell-thick and separated by sinusoids. Focal fatty change and excessive glycogen storage were observed. The tumor cells were round or polygonal in shape, resembling the surrounding parenchymal cells. Mitosis was not found. No portal tract, central vein or ductule was found within the lesion. The tumor tissue showed a positive reaction for cytokeratin (CK) 18, but not for CK19, vimentin, estrogen and progesterone receptors. Monoclonality was demonstrated for the lesion, confirming the diagnosis of an LCA. Clonality analysis is helpful for its distinction from focal nodular hyperplasia.

Pathology findings in a model of auxiliary liver transplantation with portal vein arterialization in pigs

OBJECTIVE

To determine the histological findings and temporal evolution that occur in auxiliary liver grafts as a consequence of arterialization of the portal vein (PVA).

MATERIALS AND METHODS

We evaluated 10 auxiliary heterotopic liver transplants with arterialization of the PVA. The histological study was performed using an optical microscope to process liver samples with staining using hematoxylin and eosin. A biopsy of native liver tissue was used as a control.

RESULTS

Two animals were excluded from the study, one due to ischemic necrosis of the graft and one that died 4 hours after transplant. All of the remaining eight animals underwent a histological study at 1 day, 7 days, and 14 days. The most significant histological findings were: (1) dilation of portal areas and sinusoids, which were detected at 24 hours and persisted; (2) thickening of the interlobular septum, which was observed after day 7 and progressively increased to day 14; (3) bile duct hyperplasia detected at the seventh day.

CONCLUSIONS

The consistent, early findings in a pig liver with PVA included vascular dilation of the portal area and the sinusoids, with bile duct hyperplasia extending progressively and the thickening of interlobular connective tissue septa with a generalized perilobular connective tissue reaction, which did not seem to alter the internal structure of the lobule, which showed histologically normal hepatocytes. The fibrous reaction may be the first stage in chronic hepatopathy. Further long-term studies are required in this model.

Large regenerative nodule perfused by the portal vein

In a 42-year-old Japanese woman with esophageal varices, abdominal ultrasound (US) demonstrated a hyperechoic lesion 3 cm in diameter in segment 4 (S4). This nodular lesion had high intensity on T1-weighted magnetic resonance imaging (MRI), low intensity on T2, and very high intensity on superparamagnetic iron oxide (SPIO) enhanced MRI. Angiography showed sparse distribution of arterial branches and dense distribution of portal branches in S4. Meandering, thin arteries were seen in the peripheral area of the right lobe. The second branches of the portal vein were hardly visualized anywhere in the liver. Computed tomography arterioportography (CTAP) revealed portal blood flow dominance in this nodular lesion. There was no evidence of ischemic liver damage, such as thromboembolic episodes, laboratory data of liver damage, coagulation abnormalities etc. Therefore this abnormality was more likely to be caused by anomalous changes than thrombotic changes. Needle biopsy revealed no atypical cells. Two years later, the nodule size was reduced to 1.9 cm, showing its benign nature. Based on these findings, this lesion was classified as a new type of large regenerative nodule (LRN) associated with anomalies in the portal veins and arteries. This is the first report of an LRN of this size in which portal vein perfusion was dominant. Moreover, this lesion was difficult to differentiate from hepatocellular carcinoma (HCC) by imaging. Analysis of the images and pathological features of this case would contribute to a better understanding of the pathogenesis of nodular lesions of the liver.

Differentiation of focal nodular hyperplasia and hepatocellular adenoma by contrast-enhanced ultrasound

Non-invasive differentiation of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) is difficult. The aim of this study was to assess the accuracy of contrast-enhanced phase inversion ultrasound to differentiate between histologically proven FNH and HCA, analysing the arterial and (early) portal venous phase. 32 patients with histological proven FNH (n=24) or HCA (n=8) have been included in this prospective study. Examination technique: Siemens Elegra, phase inversion harmonic imaging (PIHI) with low mechanical index (MI)<0.2-0.3 using SonoVue (BR 1). The contrast enhancing tumour characteristics were evaluated during the hepatic arterial (starting 8-22 s) and early portal venous phase (starting 12-30 s). The image analysis was performed by three examiners. In 23 of 24 patients with FNH the contrast pattern revealed pronounced arterial and (early) portal venous enhancement. Homogeneous enhancement was detected during the hepatic arterial phase in all eight patients with HCA. In contrast to patients with FNH, no enhancement was seen during the portal venous phase. In conclusion, contrast-enhanced phase inversion ultrasound demonstrated pronounced arterial and portal venous enhancement in patients with focal nodular hyperplasia. In contrast, after homogeneous enhancement during hepatic arterial phase, no enhancement during hepatic portal venous phase was detected in patients with hepatocellular adenoma. Therefore, this technique might improve the functional characterization of benign hypervascular focal liver lesions.

Focal nodular hyperplasia in identical twins

A unique case of a focal nodular hyperplasia (FNH) in identical twins is presented. The computed tomography (CT) and magnetic resonance imaging (MRI) of the abdomen demonstrated in both twins a mass of identical size in the same segment of their liver. Histopathologic examination of both masses confirmed the diagnosis of focal nodular hyperplasia. This case report strongly supports the theory of a congenital vascular anomaly playing a major role in the etiology of focal nodular hyperplasia.

Drug induced hepatic focal nodular hyperplasia

Focal nodular hyperplasia, an uncommon benign hepatic tumor, has been reported following ingestion of various drugs and chemical agents. The authors report a case of a young girl who developed such lesion following ingestion of anti-tuberculosis drugs for the treatment of her abdominal tuberculosis.

Congenital absence of the portal vein complicating hepatic tumors

Congenital absence of the portal vein (CAPV) is a rare malformation that is often accompanied by other anomalies such as cardiac and skeletal malformations and/or hepatic tumors. We describe here a case of CAPV complicating hepatic tumors in a 16-year-old Japanese girl. Abdominal ultrasonography revealed a hyperechoic tumor in the liver and dilatation of the portal vein that appeared to be connected directly with the inferior vena cava. Subsequent abdominal computed tomography (CT) revealed tumors and magnetic resonance angiography confirmed that the portal vein entered directly into the inferior vena cava just above the liver. In addition, there was absence of the right portal vein and the left intrahepatic branch except for the presence of left portal vein only within the porta hepatis. These findings led to a diagnosis of CAPV complicated hepatic tumors. Careful monitoring of these hepatic tumors is ongoing due to the possibility of malignant transformation.

Nodular regenerative hyperplasia (NRH) of the liver--a manifestation of 'organ-specific antiphospholipid syndrome'?

Nodular regenerative hyperplasia (NRH) of the liver is a local hyperplastic response of hepatocytes, probably due to vascular abnormalities. Since it was shown in a few case reports that NRH may be associated with antiphospholipid antibodies (APA) we wanted to analyze the relevance of APA in patients with this disease. Sera from 13 patients with histologically defined NRH were tested for APA by an in-house ELISA using as antigens cardiolipin (CL), beta2-glycoprotein I (beta2-gp I), phosphatidylserine (PS), and thromboplastin (TP), a mixture of different phospholipids and phospholipid-binding proteins. As controls, sera from patients with serologically and histologically defined autoimmune liver diseases (primary biliary cirrhosis n = 14; autoimmune hepatitis n = 14) without histological evidence for NRH as well as from 14 healthy blood donors were analyzed. 77% of the NRH patients had APA. In 46% they were directed against CL. In contrast, only 14% of the patients with autoimmune liver diseases and 14% of the healthy controls had anti-CL antibodies (p < 0,05). Antibodies to beta2-gp I and TP did not discriminate between NRH and autoimmune liver diseases. Anti-PS antibodies were not observed. These data indicate that determination of anti-CL antibodies in NRH may help to identify a subgroup of patients in whom an 'organ-specific antiphosholipid syndrome' of the liver may be involved in the pathogenesis.

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.

Simultaneous occurrence of adenoma, focal nodular hyperplasia, and hemangioma of the liver: are they derived from a common origin?

The association between hepatic hemangioma (HH) and focal nodular hyperplasia (FNH) or the association between FNH and hepatic adenoma (HA) has been reported. The authors report a case in which FNH, HH, and HA simultaneously appear in the liver. A 25-year-old woman was admitted to the Department of Surgery of the University of Catania (Italy), after presenting pain in the right hypocondrium. No therapy with oral contraceptives, no pregnancy and no abnormalities of the laboratory tests were found. Ultrasonography and computed tomography scans revealed four masses with the characteristics of HH, HA, FNH, and a hydatid cyst located, respectively, in segments II, IV, IV, and V of the liver. The surgical procedures performed were hemangioma and adenoma enucleation and en bloc resection of the FNH, hydatid cyst and gallbladder. No complications were recorded in the postoperative period and the patient was discharged from the hospital after 1 week. A pathological examination confirmed the preoperative diagnosis. To the best of our knowledge, the association of HH, FNH, and HA has never been reported. A common pathogenesis has clearly been demonstrated for hepatocytes and other cell types. The simultaneous presence of these three different kinds of tumor suggest that HH, FNH and HA could be the different expression of the same malformative anomaly.

Histologic scoring of liver biopsy in focal nodular hyperplasia with atypical presentation

The contribution of radio-guided transcutaneous biopsy in the diagnosis of focal nodular hyperplasia (FNH) of the liver was compared with the findings on surgical specimens to assess its contribution in clinical and radiologic atypical cases. This retrospective study involved 30 patients with atypical tumors on imaging who underwent liver biopsy and then surgery. All surgical specimens were diagnosed as FNH, either classical (n = 18) or nonclassical (n = 12). Imaging data were reviewed according to 4 radiologic criteria on magnetic resonance imaging (MRI) and/or computed tomography (CT) scan (hypervascularity, homogeneity, nonencapsulation, and presence of a central scar), and classified depending on the number of criteria found (group I, 4 of 4; group II, 3 of 4; group III, 2 or fewer). Histologic assessment of ultrasound (US)-guided liver biopsy recorded major diagnostic features (fibrous bands, thick-walled vessels, reactive ductules, and nodularity) and minor features (sinusoidal dilatation and perisinusoidal fibrosis). "Definite FNH" (3 or 4 major features) was diagnosed in 14 biopsies, "possible FNH" (2 major and 1 or 2 minor features) in 7 cases, and "negative for FNH" (2 or fewer major features without minor features) in 9 cases. The diagnosis of FNH on biopsy was reached in 14 cases (58.3%) in patients with 2 or fewer imaging criteria (group III; n = 24). Biopsies with a diagnosis of "possible FNH" corresponded to a large proportion of telangiectatic-type FNH on the specimen. In conclusion, liver biopsy does not appear to be necessary in cases in which imaging is typical. However, the absence of radiologic diagnostic criteria in FNH does not preclude a positive diagnosis on liver needle biopsy. Using the proposed histologic scoring system, surgical management may be avoided in these cases.

Hepatocellular carcinoma in a patient with focal nodular hyperplasia

BACKGROUND

Focal nodular hyperplasia is an uncommon liver tumour that typically requires no therapeutic intervention.

CASE OUTLINE

A 43-year-old woman with a 20-year history of oral contraceptive use presented with symptomatic bilateral liver masses. Biopsy revealed hepatocellular carcinoma in the right hemiliver and focal nodular hyperplasia in the left hemiliver. At operation,t he patient was noted to have multiple liver nodules bilaterally, and all intraoperative biopsies were consistent with focal nodular hyperplasia including a biopsy taken from the region that demonstrated carcinoma preoperatively. Because of the earlier biopsy results and the patient's preoperative symptoms, a right hemihepatectomy was performed. Final pathology revealed hepatocellular carcinoma directly adjacent to an area of focal nodular hyperplasia, as well as multiple other areas of hyperplastic liver tumour.

DISCUSSION

Although focal nodular hyperplasia is believed to be benign, few studies have followed patients with this tumour beyond three years. Longer-term follow-up studies are needed to determine the natural history of focal nodular hyperplasia, potentially focussing on a subset of patients with either diffuse tumours or prolonged oral contraceptive use.

Benign nodular hepatocellular lesions caused by abnormal hepatic circulation: etiological analysis and introduction of a new concept

Problems in definitive diagnosis and etiology of various benign nodular hepatocellular lesions were evaluated. Of these lesions, focal nodular hyperplasia (FNH), nodular regenerative hyperplasia (NRH), nodular lesions associated with idiopathic portal hypertension (IPH), non-cirrhotic large regenerative nodules (LRN), hepatocellular adenoma (HA)-like hyperplastic nodules, and partial nodular transformation (PNT) have been suggested to be related to abnormal hepatic circulation. However, the following points are considered to need further clarification: (i) is the abnormal circulation caused by thrombosis, vasculitis, or congenital anomaly?; (ii) is thrombosis a cause or a result of congestion?; (iii) are impaired blood vessels primarily the portal veins or arteries?; (iv) how are these disorders related to various syndromes, immunological abnormalities and abnormal blood flow of other organs, which are reported to coexist with these lesions often?; and (v) how should non-typical cases, which differ from typical cases, be interpreted? In addition, a concept that may lead to solving these problems (anomalous portal tract syndrome; a hypothesis that congenital vascular anomaly is the origin of these benign nodular hepatocellular lesions) was introduced.

Clinicopathological study of a hilar nodule in the livers of long-term survivors with biliary atresia

With the application of liver transplantation for patients with biliary atresia (BA), we have had the opportunity to review the clinicopathologic features of the native livers from 10 transplanted BA patients. A single large nodule at porta hepatis (hilar nodule) was noted in three of 10 patients, and an ill-defined nodule-like lesion at porta hepatis was present in two other patients. The three BA patients with hilar nodules were long-term survivors, compared to the patients with nodule-like and those without nodules. The hilar nodules measured between 5.0 cm and 8.0 cm and histologically, they were partly surrounded by fibrous septa with relatively well-preserved liver architectures and fewer inflammatory cells at the portal triads when compared to the surrounding cirrhotic lesions. No nuclear or cellular atypia was observed. Proliferating cell nuclear antigen labeling index was higher in the surrounding cirrhotic lesions than the hilar nodules. The nodule-like lesions at porta hepatis also showed similar light microscopic and immunohistochemical features as the hilar nodules. These hilar nodules did not seem to contain any malignant potential. The benign histology with relatively well-preserved liver architecture and the preferential site of occurrence at porta hepatis where bile seemed to flow more smoothly, suggested possible residues of less-affected hepatic tissues.

Oral contraceptive use and focal nodular hyperplasia of the liver

BACKGROUND & AIMS

Because most patients with focal nodular hyperplasia (FNH) are young women, an important decision is whether to discontinue oral contraceptive (OC) use. The aims of this study were to evaluate (1) the number and size of FNH lesions in women with various patterns of OC use and in women without OC use and (2) the modifications in the number and size of FNH lesions during follow-up, according to OC use.

METHODS

In a 9-year study in 216 women with FNH, the diameter and number of lesions documented by magnetic resonance (MR) imaging were evaluated (1) at diagnosis according to OC use as follows: group A, no OC use (n = 28); group B, high-dose OC use (n = 46); group C, low-dose OC use (n = 98); group D, successive use of high-dose and low-dose OCs (n = 33); and group E, use of progestogens only (n = 11); and (2) during follow-up in 136 women, 14 of whom were OC nonusers who stayed off OCs, 89 discontinued OC use, 26 took low-dose OCs, and 7 stayed on a progestogen only. Twelve women became pregnant. In 168 women, the diagnosis of FNH was made based on a combination of rigorously defined MR criteria. In the remaining 48 patients, diagnosis was by surgical biopsy (n = 36) or resection (n = 12). Mean diameter and number of lesion(s) per patient were assessed by MR imaging using the same protocol in all study patients.

RESULTS

No significant differences in the number or size of lesions were found in the 5 patient groups. During follow-up, a change in lesion diameter occurred in only 4 women; this event was not influenced by OC use. In the 12 patients who became pregnant, lesion size was unchanged after delivery, pregnancy was uneventful, and delivery occurred spontaneously.

CONCLUSIONS

These data suggest that (1) neither the size nor the number of FNH lesions are influenced by OC use; (2) size changes during follow-up are rare and do not seem to depend on OC use; and (3) pregnancy is not associated with FNH changes or complications.