A Shifting Paradigm in Diagnosis and Management of Hepatic Adenoma.

BACKGROUND: New insights into molecular pathogenesis of hepatocellular adenomas (HCA) have allowed sub-classification based on distinct genetic alterations and a fresh look at characterizations of natural history. Clinically, this is important in understanding risk factors for two feared complications: malignant transformation and hemorrhage. METHODS: PubMed literature search for hepatocellular adenoma over all years, excluding case reports and articles focusing on multiple adenomas or adenomatosis. RESULTS: The ß-catenin exon 3 mutated HCA accounts for about 10% of all HCAs and is associated with the highest risk of malignant transformation. The HF1α subtype accounts for 30-40% of all HCAs and has the lowest risk of malignant transformation. Gender has also emerged as an increasingly important risk factor and males with HCA are at considerably higher risk of malignant transformation, regardless of tumor size. The increasing use of gadoxetic-enhanced MRI has allowed for improved differentiation of HCAs from focal nodular hyperplasia, as well as the identification of specific radiologic features of some subtypes, particularly the inflammatory and HF1α HCAs. CONCLUSIONS: Classification of HCA by subtype has important implications for patient counseling and treatment given variable risks of malignant transformation and hemorrhage. Males and those with ß-catenin exon 3 mutated HCAs are two groups who should always be counselled to undergo surgical resection. On the other hand, in the lower risk HF1α subtype observation is appropriate in lesions < 5 cm and may even be considered in larger lesions as longer follow-up data is aggregated and tumorigenesis is better understood.

OATPB1/B3 and MRP3 expression in hepatocellular adenoma predicts Gd-EOB-DTPA uptake and correlates with risk of malignancy.

BACKGROUND AND AIMS: Hepatobiliary phase (HBP) Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) has increased the accuracy in differentiating focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA). However, the ability of this technique to distinguish HCA subtypes remains controversial. The aim of this study was to investigate the expression of hepatocyte transporters (OATPB1/B3, MRP2, MRP3) in HCA subtypes, hence to understand their MRI signal intensity on HBP Gd-EOB-DTPA-enhanced MRI. METHODS: By means of immunohistochemistry (IHC), we scored the expression of OATPB1/B3, MRP2 and MRP3, in resected specimens of FNH (n = 40), subtyped HCA (n = 58) and HCA with focal malignant transformation (HCA-HCC, n = 4). Results were validated on a supplementary set of FNH (n = 6), subtyped HCA (n = 17) and HCA-HCC (n = 1) with Gd-EOB-DTPA MR images. RESULTS: All FNH showed a preserved expression of hepatocytes transporters. Beta-catenin-activated HCA (at highest risk of malignant transformation) and HCA-HCC were characterized by preserved/increased OATPB1/B3 expression (predictor of hyperintensity on HBP), as opposed to other HCA subtypes (P < 0.01) that mostly showed OATPB1/B3 absence (predictor of hypointensity on HBP). HCA-HCC showed an additional MRP3 overexpressed profile (P < 0.01). On HBP Gd-EOB-DTPA-enhanced MRI, FNH and HCA signal intensity reflected the profile predicted by their specific OATPB1/B3 tissue expression. The hyperintense vs hypointense HBP signal criterion was able to distinguish all higher risk HCA and HCA-HCC (100% accuracy). CONCLUSIONS: OATPB1/B3 and MRP3 IHC and signal intensity on HBP Gd-EOB-DTPA-enhanced MRI can help to stratify HCA according to their risk of malignant transformation.

MicroRNA Expression in Focal Nodular Hyperplasia in Comparison with Cirrhosis and Hepatocellular Carcinoma.

The liver disease focal nodular hyperplasia (FNH) has several histological features that resemble hepatic cirrhosis. Since cirrhosis may develop further into hepatocellular carcinoma (HCC) contrary to FNH, the aim of the present study was to identify microRNAs (miRNA), which, by their altered expression levels, may be associated with the benign, tumor-like nature of FNH. Altogether 106 surgically removed formalin-fixed paraffin-embedded liver samples were selected, including 22 FNH, 45 cirrhosis, 24 HCC and 15 normal liver tissues. Etiology of the cases of cirrhosis and HCC includes hepatitis C and alcoholism and the HCC cases developed in cirrhotic livers. Relative expression levels of 14 miRNAs were determined using TaqMan MicroRNA Assays. In comparison to normal liver, the levels of miR-34a and miR-224 were elevated not only in FNH but also in cirrhosis and HCC, while the expression of miR-17-5p, miR-18a and miR-210 was decreased in FNH. Further, the levels of miR-21 and miR-222 were increased in cirrhosis and HCC but were decreased in FNH and the expression of miR-17-5p, miR-18a, miR-195 and miR-210 was decreased in FNH as compared with cirrhosis and/or HCC. In conclusion, the elevation of miR-34a and miR-224 may be associated with both benign and malignant proliferative processes, nevertheless the increased expression of oncomiRs miR-21 and miR-222 in cirrhosis and HCC but not in FNH may be related to malignant processes of the liver. The decreased levels of miR-18a, miR-195 and miR-210 may further differentiate FNH from cirrhosis, reflecting the different pathogenesis of these two entities contrary to some histologically similar features.

Molecular patterns of diffuse and nodular parathyroid hyperplasia in long-term hemodialysis.

Secondary hyperparathyroidism is a well-known complication of end-stage renal disease (ESRD). Both nodular and diffuse parathyroid hyperplasia occur in ESRD patients. However, their distinct molecular mechanisms remain poorly understood. Parathyroid tissue obtained from ESRD patients who had undergone parathyroidectomy was used for Illumina transcriptome screening and subsequently for discriminatory gene analysis, pathway mapping, and gene annotation enrichment analysis. Results were further validated using quantitative RT-PCR on the independent larger cohort. Microarray screening proved homogeneity of gene transcripts in hemodialysis patients compared with the transplant cohort and primary hyperparathyroidism; therefore, further experiments were performed in hemodialysis patients only. Enrichment analysis conducted on 485 differentially expressed genes between nodular and diffuse parathyroid hyperplasia revealed highly significant differences in Gene Ontology terms and the Kyoto Encyclopedia of Genes and Genomes database in ribosome structure (P = 3.70 × 10-18). Next, quantitative RT-PCR validation of the top differently expressed genes from microarray analysis proved higher expression of RAN guanine nucleotide release factor (RANGRF; P < 0.001), calcyclin-binding protein (CACYBP; P < 0.05), and exocyst complex component 8 (EXOC8; P < 0.05) and lower expression of peptidylprolyl cis/trans-isomerase and NIMA-interacting 1 (PIN1; P < 0.01) mRNA in nodular hyperplasia. Multivariate analysis revealed higher RANGRF and lower PIN1 expression along with parathyroid weight to be associated with nodular hyperplasia. In conclusion, our study suggests the RANGRF transcript, which controls RNA metabolism, to be likely involved in pathways associated with the switch to nodular parathyroid growth. This transcript, along with PIN1 transcript, which influences parathyroid hormone secretion, may represent new therapeutical targets to cure secondary hyperparathyroidism.

Multiple ß-catenin mutations in hepatocellular lesions arising in Abernethy malformation.

An 18-year-old man underwent liver transplantation due to an Abernethy malformation associated with multiple hepatocellular nodules including one which was rapidly enlarging and was suspicious for malignant transformation. Analysis of the explanted liver showed a spectrum of multiple hepatocellular nodules ranging in appearance from focal nodular hyperplasia, hepatocellular adenoma and to a well-differentiated hepatocellular neoplasm borderline for hepatocellular carcinoma. Mutational analysis revealed wild-type ß-catenin expression in the background liver and some nodules, whilst different variants were present in other lesions irrespective of their morphological appearance. No telomerase reverse transcriptase (TERT) promoter mutation was identified. Abernethy malformations can lead to independent genetic events which can result in ß-catenin mutations associated with malignant transformation of hepatocellular nodules. When following up such patients, one must therefore have a high index of suspicion, particularly if radiological surveillance reveals a change in the nature of hepatic lesions.

DICER1 Mutations and Differentiated Thyroid Carcinoma: Evidence of a Direct Association.

CONTEXT: DICER1 germline mutation carriers have an increased predisposition to cancer, such as pleuropulmonary blastoma (PPB) and Sertoli-Leydig cell tumor (SLCT), and a high prevalence of multinodular goiter (MNG). Although differentiated thyroid carcinoma (DTC) has been reported in some DICER1 mutation carriers with PPB treated with chemotherapy, the association of DTC with DICER1 mutations is not well established. CASE DESCRIPTION: We report a family with DICER1 mutation and familial DTC without a history of chemotherapy. A 12-year-old female (patient A) and her 14-year-old sister (patient B) presented with MNG. Family history was notable for a maternal history of DTC and bilateral ovarian SLCT. Both sisters underwent total thyroidectomy. Pathological examination showed nodular hyperplasia and focal papillary thyroid carcinoma within hyperplastic nodules. Subsequently, patient A developed virilization secondary to a unilateral ovarian SLCT. During her evaluation, an incidental cystic nephroma was also found. Three other siblings had MNG on surveillance ultrasound examination; two had thyroidectomies, and one had two microscopic foci of papillary carcinoma. Patient A, her mother, and four affected siblings had a germline heterozygous pathogenic DICER1 mutation c.5441C>T in exon 25, resulting in an amino acid change from p.Ser1814Leu of DICER1. Somatic DICER1 RNase IIIb missense mutations were identified in thyroid nodules from three of the four siblings. CONCLUSIONS: This family provides novel insight into an emerging phenotype for DICER1 syndrome, with evidence that germline DICER1 mutations are associated with an increased risk of developing familial DTC, even in the absence of prior treatment with chemotherapy.

Gene expression of growth factors and growth factor receptors for potential targeted therapy of canine hepatocellular carcinoma.

The purpose of this study was to evaluate the gene expression of growth factors and growth factor receptors of primary hepatic masses, including hepatocellular carcinoma (HCC) and nodular hyperplasia (NH), in dogs. Quantitative real-time reverse transcriptase-polymerase chain reaction was performed to measure the expression of 18 genes in 18 HCCs, 10 NHs, 11 surrounding non-cancerous liver tissues and 4 healthy control liver tissues. Platelet-derived growth factor-B (PDGF-B), transforming growth factor-α, epidermal growth factor receptor, epidermal growth factor and hepatocyte growth factor were found to be differentially expressed in HCC compared with NH and the surrounding non-cancerous and healthy control liver tissues. PDGF-B is suggested to have the potential to become a valuable ancillary target for the treatment of canine HCC.

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.

Hepatocellular benign tumors-from molecular classification to personalized clinical care.

Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are benign hepatocellular tumors that develop most frequently in women without cirrhosis. Genomic approaches have identified signaling pathways related to these benign hepatocyte proliferations. FNH, a polyclonal lesion, is characterized by local vascular abnormalities and heterogeneous activation of Wnt/ß-catenin and transforming growth factor ß signaling. Four major subgroups of HCAs have been identified based on mutations in specific oncogenes and tumor suppressor genes. Each molecular subtype of HCA has been associated with specific pathways, providing new information about benign tumorigenesis. Key features include metabolic alterations (induced by defects in HNF1A), oncogene-induced inflammation (activation of JAK-STAT signaling in inflammatory adenomas), and an association between activation of Wnt/ß-catenin signaling and progression of HCAs in hepatocellular carcinomas. Benign hepatocellular tumors can be classified using immunohistochemical analyses. Studies of genotypes and phenotypes of FNH and HCAs have led to the identification of risk factors and improved invasive and noninvasive diagnostic techniques, evaluation of prognosis, and treatment. We review the molecular pathways involved in benign hepatocyte proliferation and discuss how this basic knowledge has been progressively translated into personalized clinical care.

Focal nodular hyperplasia and hepatocellular adenoma: current views.

Focal Nodular Hyperplasia (FNH) is a rare benign hepatic lesion believed to generate upon a hyperplastic response of the hepatocyte. Hepatocellular Adenoma (HA) occurs predominantly in young women receiving oral contraceptive medication. These two lesions have drawn significant attention throughout the recent years due to their specific clinical and pathological features as well as their challenging management. Although Focal Nodular Hyperplasia is managed conservatively in the majority of cases, it can albeit pose a difficult diagnostic dilemma. On the other hand, Hepatocellular Adenoma can be complicated with catastrophic hemorrhage or malignant transformation and therefore mandates surgical excision in many cases. The aim of this work is to review the current literature pertaining to these two clinical entities regarding their pathogenesis, diagnostic approach and genetics, as well as to shed light on specific differential diagnostic issues arising in many cases these lesions are encountered.

MYC-regulated genes involved in liver cell dysplasia identified in a transgenic model of liver cancer.

Foci of liver cell dysplasia (LCD) are distinct morphological entities and may evolve into hepatocellular carcinomas (HCCs). While most HCCs overexpress c-Myc, its role in LCD remains uncertain. Therefore, a c-Myc transgenic model of HCC was investigated to understand the genetic events forcing liver cells into dysplasia and subsequent malignant transformation. Specifically, whole genome scans enabled fingerprinting of genes at different stages of disease, ie LCD and HCC, while laser microdissected LCD lesions were used to validate regulation of candidate genes by quantitative real-time RT-PCR, ie Mybbp1a, Rps7, Rps19, Rpl10a, Skp1a, Tfdp1, Nhp2, and Bola2. EMSA band shift assays confirmed c-Myc DNA binding at regulatory sequences of candidate gene-specific promoters. Additionally, published ChIP-seq data helped to define the candidate genes as c-Myc bona fide targets. Treatment of the human hepatoma cell line HepG2 with hepatic growth factor (Hgf) caused c-Myc protein induction and transcriptional up-regulation of candidate genes, albeit at different levels when individual genes were compared. A significant increase of HepG2 entering the G1-phase was associated with up-regulation of the candidate genes in an Hgf concentration-dependent matter. Finally, we confirmed regulation of candidate genes in patients' samples with low- and high-grade dysplasia and HCC staged T1 to T3, while their expression was unchanged in focal nodular hyperplasia and hepatic adenoma, therefore asserting the diagnostic value and clinical significance of these candidate genes. Overall, novel c-Myc targeted genes were identified and may contribute to hepatocyte transformation by altering cell cycle control, thereby contributing to c-Myc's oncogenic activity.

Disruption of Notch1 induces vascular remodeling, intussusceptive angiogenesis, and angiosarcomas in livers of mice.

BACKGROUND & AIMS: Notch signaling mediates embryonic vascular development and normal vascular remodeling; Notch1 knockout mice develop nodular regenerative hyperplasia (NRH). The pathogenesis of NRH is unclear, but has been associated with vascular injury in the liver sinusoids in clinical studies. We investigated the role of Notch1 signaling in liver sinusoidal endothelial cells (LSECs). METHODS: We studied MxCre Notch1(lox/lox) mice (conditional knockout mice without tissue-specific disruption of Notch1); mice with hepatocyte-specific knockout were created by crossing Notch1(lox/lox) with AlbCre(+/-) mice. Portal vein pressure was measured; morphology of the hepatic vasculature was assessed by histologic and scanning electron microscopy analyses. We performed functional and expression analyses of isolated liver cells. RESULTS: MxCre-induced knockout of Notch1 led to NRH, in the absence of fibrosis, with a persistent increase in proliferation of LSECs. Notch1 deletion led to de-differentiation, vascular remodeling of the hepatic sinusoidal microvasculature, intussusceptive angiogenesis, and dysregulation of ephrinB2/EphB4 and endothelial tyrosine kinase. Time-course experiments revealed that vascular changes preceded node transformation. MxCre Notch1(lox/lox) mice had reduced endothelial fenestrae and developed portal hypertension and hepatic angiosarcoma over time. In contrast, mice with hepatocyte-specific disruption of Notch1 had a normal phenotype. CONCLUSIONS: Notch1 signaling is required for vascular homeostasis of hepatic sinusoids; it maintains quiescence and differentiation of LSECs in adult mice. Disruption of Notch1 signaling in LSECs leads to spontaneous formation of angiosarcoma, indicating its role as a tumor suppressor in the liver endothelium.

Recent advances in cytogenetics and molecular biology of adult hepatocellular tumors: implications for imaging and management.

Focal nodular hyperplasia (FNH), hepatocellular adenoma (HCA), and hepatocellular carcinoma (HCC) compose hepatocellular neoplasms that occur in adults. These tumors demonstrate characteristic epidemiologic and histopathologic features and clinical and imaging manifestations. HCAs are monoclonal neoplasms characterized by increased predilection to hemorrhage or rupture and occasional transformation to HCC. On the other hand, FNH is a polyclonal tumorlike lesion that occurs in response to increased perfusion and has an indolent clinical course. Up to 90% of HCCs occur in the setting of cirrhosis. Chronic viral hepatitis (hepatitis B and hepatitis C) infection and metabolic syndrome are major risk factors that can induce HCCs in nonfibrotic liver. Recent advances in pathology and genetics have led to better understanding of the histogenesis, natural history, and molecular events that determine specific oncologic pathways used by these neoplasms. HCAs are now believed to result from specific genetic mutations involving TCF1 (transcription factor 1 gene), IL6ST (interleukin 6 signal transducer gene), and CTNNB1 (ß catenin-1 gene); FNHs are characterized by an "imbalance" of angiopoietin. While the ß catenin signaling pathway is associated with well- and moderately differentiated HCCs, mutations involving p53 (tumor protein 53 gene), MMP14 (matrix metalloproteinase 14 gene), and RhoC (Ras homolog gene family, member C) are associated with larger tumor size, higher tumor grade with resultant shortened tumor-free survival, and poor prognosis. Fibrolamellar carcinoma (FLC), a unique HCC subtype, exhibits genomic homogeneity that partly explains its better overall prognosis. On the basis of recent study results involving cytogenetics and oncologic pathways of HCCs, novel drugs that act against molecular targets are being developed. Indeed, sorafenib (a multikinase inhibitor) is currently being used in the successful treatment of patients with advanced HCC. Characterization of genetic abnormalities and genotype-phenotype correlations in adult hepatocellular tumors provides better understanding of tumor pathology and biology, imaging findings, prognosis, and response to molecular therapeutics.

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.

Clonality of nodular lesions in liver cirrhosis and chromosomal abnormalities in monoclonal nodules of altered hepatocytes.

AIMS: To investigate the clonality and chromosome abnormalities of nodules of altered hepatocytes (NAH) in liver cirrhosis and determine whether there is a genetic link between monoclonal NAH and hepatocellular carcinoma (HCC). METHODS AND RESULTS: First, 93 nodules from nine hepatitis B virus (HBV)-related liver cirrhosis patients were dissected by laser microdissection. Next, genomic DNA was extracted, pretreated with Hpa II or Hha I, and amplified via nested polymerase chain reaction for the phosphoglycerate kinase and androgen receptor genes. Finally, the chromosomal aberrations of 12 monoclonal NAH were studied using array-based comparative genomic hybridization (array-CGH). Loss of X chromosomal inactivation mosaicism was demonstrated in three large regenerative nodules and 12 NAH with small cell change (SCC), indicating their neoplastic nature. Among the 60 NAH without SCC, 29 (48.33%) were shown to be monoclonal, whereas four glycogen-storing foci and 14 regenerative nodules were found to be polyclonal. Array-CGH analysis revealed chromosomal abnormalities in one NAH with SCC. Moreover, a part of chromosomal abnormalities in the NAH with SCC coincided with those in HCC. CONCLUSIONS: Some (48.33%) NAH in HBV-associated cirrhosis, particularly all those with SCC, are already neoplastic lesions. Occurrence of SCC is a late event during NAH progression, suggesting a premalignant phenotype.

Follicular variant of papillary carcinoma: reproducibility of histologic diagnosis and utility of HBME-1 immunohistochemistry and BRAF mutational analysis as diagnostic adjuncts.

CONTEXT: Despite the recognition of the follicular variant of papillary carcinoma of the thyroid (FVPTC) for over 50 years, reproducibility of this diagnostic category has remained poor. Architectural features have been of variable utility as some FVPTC seem encapsulated, whereas others are multifocal and may be confused with nodular hyperplasia. Nuclear features are important for diagnosis of FVPTC, but some authors have discounted the utility of nuclear grooves and inclusions. More recently, BRAF and HBME-1 (Human Bone Marrow Endothelial Cell-1) have been suggested as markers for FVPTC. OBJECTIVE: To investigate the frequency of BRAF mutations and HBME-1 immunopositivity, in a series of FVPTCs in which the diagnosis was established by 100% consensus among a panel of 6 surgical pathologists. DESIGN: Twenty-eight specimens with an original diagnosis of FVPTC and 10 cases with other diagnoses were obtained from the surgical pathology files of the University of Utah School of Medicine. All specimens were independently reviewed by 6 surgical pathologists. Tissue blocks were analyzed for BRAF exon 15 mutations and HMBE-1 expression. RESULTS: Complete agreement among pathologists for the diagnosis of FVPTC was obtained in 28.6% (8/28) of cases originally diagnosed as FVPTC. Mutations in BRAF exon 15 were found in 25% (2/8) of cases with a 100% consensus diagnosis of FVPTC and 32% (6/19) of cases unanimously diagnosed as a type of papillary carcinoma (classic or follicular variant). HBME-1 was expressed in 87.5% (7/8) of lesions with a 100% consensus diagnosis of FVPTC and 84.2% (16/19) of lesions with a unanimous diagnosis of a type of papillary carcinoma of the thyroid (classic or follicular variant). CONCLUSIONS: Interobserver agreement for the diagnosis of FVPTC is poor and testing for the BRAF mutation is only marginally helpful because a minority of FVPTCs possess the mutation. HBME-1 expression when coupled with a BRAF mutation, results in 100% specificity but low sensitivity for the presence of papillary carcinoma of the thyroid including the follicular variant.

[Highly differentiated liver tumors: recent developments and their diagnostic application]. / Hochdifferenzierte Lebertumoren: Neue Entwicklungen und ihre diagnostische Relevanz.

Biopsy diagnosis of early and highly differentiated liver tumors is one of the most challenging tasks in histopathology. During recent years its parameters have changed fundamentally due to shifting clinical algorithms. Modern histopathology has met this challenge by defining new, prognostically relevant subtypes of early hepatocellular carcinoma and by elaborating morphological algorithms and novel immunohistological markers for the differential diagnosis of highly differentiated hepatocellular tumors. In addition, a new, predictive molecular pathological and histological classification of liver cell adenoma has been developed. By means of the consequent application of these new diagnostic tools, together with the so-called 'matrix diagnosis', a reliable diagnosis is achieved in the vast majority of these difficult cases.

Clonality and allelotype analyses of focal nodular hyperplasia compared with hepatocellular adenoma and carcinoma.

AIM: To identify clonality and genetic alterations in focal nodular hyperplasia (FNH) and the nodules derived from it. METHODS: Twelve FNH lesions were examined. Twelve hepatocellular adenomas (HCAs) and 22 hepatocellular carcinomas (HCCs) were used as references. Nodules of different types were identified and isolated from FNH by microdissection. An X-chromosome inactivation assay was employed to describe their clonality status. Loss of heterozygosity (LOH) was detected, using 57 markers, for genetic alterations. RESULTS: Nodules of altered hepatocytes (NAH), the putative precursors of HCA and HCC, were found in all the FNH lesions. Polyclonality was revealed in 10 FNH lesions from female patients, and LOH was not detected in any of the six FNH lesions examined, the results apparently showing their polyclonal nature. In contrast, monoclonality was demonstrated in all the eight HCAs and in four of the HCCs from females, and allelic imbalances were found in the HCAs (9/9) and HCCs (15/18), with chromosomal arms 11p, 13q and 17p affected in the former, and 6q, 8p, 11p, 16q and 17p affected in the latter lesions in high frequencies (> or = 30%). Monoclonality was revealed in 21 (40%) of the 52 microdissected NAH, but was not found in any of the five ordinary nodules. LOH was found in all of the 13 NAH tested, being highly frequent at six loci on 8p, 11p, 13q and 17p. CONCLUSION: FNH, as a whole, is polyclonal, but some of the NAH lesions derived from it are already neoplastic and harbor similar allelic imbalances as HCAs.

Use of X-chromosome inactivation pattern and laser microdissection to determine the clonal origin of focal nodular hyperplasia of the liver.

AIM: To determine the clonal origin of the whole lesion and each nodule of focal nodular hyperplasia (FNH) and elucidate its nature, simultaneously comparing the clonal composition with hepatocellular adenoma (HA). METHODS: Nine FNHs from eight women, two HAs and four hepatocellular carcinomas (HCCs) were examined by clonality assays based on X-chromosomal inactivation mosaicism in females and laser microdissection. Genomic DNA was isolated from each nodule, the whole lesion and surrounding liver parenchyma, pretreated with Hpa II or Hha I, and amplified via nested PCR for phosphoglycerate kinase (PGK) and androgen receptor (AR) genes. The single nucleotide polymorphism at the PGK locus was identified by incubation with Bst XI and agarose gel electrophoresis, and the CAG repeat length polymorphism at AR locus was revealed on denaturing polyacrylamide gels and visualised by silver staining. RESULTS: Monoclonality was confirmed in both of the two HAs and all of the four HCCs examined, while polyclonality was shown in all nine FNHs as determined by the whole lesions, demonstrating their distinction from neoplastic lesions. A total of 108 nodules, including 96 nodules of altered hepatocytes (NAH) and 12 ordinary regenerative nodules (ORN), were microdissected from eight of the nine FNH lesions. Loss of X-chromosomal inactivation mosaicism was demonstrated in 39 (40.6%) of 96 NAHs, indicating the monoclonal, neoplastic nature. In contrast, polyclonality was demonstrated in all of the 12 ORNs and the surrounding liver parenchyma. CONCLUSIONS: FNH is composed of numerous NAHs and ORNs. The whole lesion shows a polyclonal cell composition, but neoplastic transformation has occurred in some of the nodules. Clonal assay is useful for its distinction from HA, and sampling the whole or larger part of the lesion is necessary.

Familial idiopathic pulmonary fibrosis in association with bone marrow hypoplasia and hepatic nodular regenerative hyperplasia: a new "trimorphic" syndrome.

This is the first report of familial idiopathic pulmonary fibrosis associated with hepatic nodular regenerative hyperplasia and bone marrow hypoplasia. Four members of one family presented with this triad of organ dysfunction. The response to immunosuppressive treatment was poor and all four members succumbed to the disease processes. The current literature is reviewed and mechanisms that could have been involved in the development of this new syndrome are proposed.