The identification of small nodules in liver adenomatosis

Benign liver tumours: understanding molecular physiology to adapt clinical management

Improvements in understanding the pathophysiology of the different benign liver nodules have refined their nosological classification. New criteria have been identified using imaging, histology and molecular analyses for a precise diagnosis of these tumours. Improvement in the classification of liver tumours provides a more accurate prediction of disease progression and has modified patient management. Haemangioma and focal nodular hyperplasia, the most common benign liver tumours that develop in the absence of chronic liver disease, are usually easy to diagnose on imaging and do not require specific treatment. However, hepatocellular adenomas and cirrhotic macronodules can be difficult to discriminate from hepatocellular carcinoma. The molecular subtyping of hepatocellular adenomas in five major subgroups defined by HNF1A inactivation, β-catenin mutation in exon 3 or exon 7/8, and activation of inflammatory or Hedgehog pathways helps to identify the tumours at risk of malignant transformation or bleeding. New clinical, biological and molecular tools have gradually been included in diagnostic and treatment algorithms to classify benign liver tumours and improve patient management. This Review aims to explain the main pathogenic mechanisms of benign liver tumours and how this knowledge could influence clinical practice.

Hepatocellular Adenoma: What We Know, What We Do Not Know, and Why It Matters

In the last 2 decades there has been significant progress in research and diagnosis of hepatocellular adenoma (HCA), resulting in the establishment of a molecular and immunohistological HCA classification. This review aims to fine-tune the current expertise in order to enhance the histopathological diagnostic possibilities, by refining issues that are already known, addressing diagnostic difficulties and identifying still unknown aspects of HCA. We will discuss novel methods to identify HCA subtypes, in particular the sonic hedgehog HCAs and the interpretation of glutamine synthetase patterns for the recognition of beta-catenin mutated HCAs. The major complications of HCAs, bleeding and malignant transformation, will be considered, including the dilemmas of atypical and borderline lesions. Paragraphs on HCAs in different clinical and geographical settings, e.g. pregnancy, cirrhosis and non-western countries are included. The natural history of the different HCA subtypes in relation with age, sex and risk factors is a feature still insufficiently investigated. This is also true for the risks of clinical bleeding and malignant transformation in association with HCA subtypes. As HCA is a relatively rare tumor, a multicenter and multidisciplinary approach across geographical boundaries will be the appropriate method to establish prospective programs to identify, classify and manage HCAs, focusing on several aspects, e.g. etiology, underlying liver disease, complications, regression and growth. Updating what we know, identifying and addressing features that we do not know matters to warrant optimal patient management.

Liver adenomatosis in patients with hepatocyte nuclear factor-1 alpha maturity onset diabetes of the young (HNF1A-MODY): Clinical, radiological and pathological characteristics in a French series

BACKGROUND

Liver adenomatosis (LA) is a rare disease resulting from biallelic inactivation of the hepatocyte nuclear factor-1 alpha (HNF1A) gene, which induces the proliferation of adenoma cells in liver parenchyma. Liver adenomatosis has only been documented in case reports from patients carrying a HNF1A germline mutation. We have evaluated the frequency of LA among a large cohort of patients with HNF1A-maturity onset diabetes of the young (MODY), previously termed "MODY3," and herein describe its clinical, radiological, and pathological characteristics.

METHODS

In all, 137 HNF1A-MODY subjects from 74 families were screened by liver ultrasonography in 13 centers, and 15 additional cases of LA were later included in the series. Liver adenomatosis was confirmed by liver computed tomography, magnetic resonance imaging (MRI), and/or histopathology.

RESULTS

Among 137 carriers of an HNF1A mutation, 9 patients (6.5%) from seven families were diagnosed with LA. Diabetes mellitus was present in 87.5% of patients with LA. In 25% of patients, LA was diagnosed due to intra-abdominal or intratumoral bleeding. Liver biochemistry was near normal in all patients. Liver imaging showed adenomas of various sizes and numbers. On MRI, most nodules had the radiological characteristics of steatotic adenomas. Histopathological confirmation of LA was available in 13 cases, and these adenomas were mostly steatotic. Surgery was initially performed in 37.5% of patients, and liver disease progression was observed in 30%. No disease progression was observed in 14 pregnancies.

CONCLUSIONS

The frequency of LA in a cohort of screened HNF1A-MODY patients and the high incidence of LA progression and/or hemorrhage warrants systematic screening for liver adenomatosis in HNF1A-MODY families.

Repeat surgery in HNF1alpha-inactivated adenomatosis

BACKGROUND AND AIMS

Stopping oral contraceptives following nodule detection usually prevents further hepatocellular growth (HCA); rare cases of growth have been reported after surgery. The aim of the study was to review our resected HCA cases and their outcomes and more specifically, growth.

METHODS

We retrieved all HCA cases that required a second intervention and HCA growth cases of none resected HCA after resection of one or several HCAs.

RESULTS

Out of the 210 resected classified HCA cases, a second resection was performed in 5 cases, 4 of which were in women with HNF1alpha-inactivated adenomatosis (H-adenomatosis) and had a favorable outcome. The fifth case was the occurrence of an inflammatory HCA, 3 years after resection of a previous one. Of the 65 resected HNF1-inactivated HCAs (H-HCAs), the nodules that remained continued to increase very slowly in 3 adenomatosis cases. After surgery, the liver became dysmorphic years later in one case, and the nodules grew but not significantly in another case. After the diagnosis of adenomatosis, progressive growth leads to surgery 12 years later in the last case.

CONCLUSION

These results confirm that, in rare H-adenomatosis, size of nodules may increase very slowly, probably in part through coalescence of micro H-HCAs and leading occasionally to a second resection.

Unexpected discovery of small HNF1α-inactivated hepatocellular adenoma in pathological specimens from patients resected for liver tumours

BACKGROUND AND AIMS

It is rare but not uncommon to discover micro/small HNF1α-inactivated hepatocellular adenoma (H-HCA) outside the context of resected H-HCA. We aimed to review our cases of micro/small H-HCA discovered by chance on different kinds of liver resected specimens.

METHODS

We retrieved cases of micro/small H-HCA discovered by chance on resected specimens outside the context of H-HCA. All these nodules were liver fatty acid binding protein (LFABP)-negative contrasting with normal positivity in the surrounding non-tumoural liver, ruling out the possibility of focal steatosis or other subtypes of micro-HCAs.

RESULTS

We identified 19 micro/small H-HCA cases. In 16 cases they were discovered in patients who underwent surgery for benign nodules including one haemangioma, six focal nodular hyperplasia, seven inflammatory HCA (including one with b-catenin activation), one HCA, whose subtype could not be identified because of massive necrosis/hemorrhage, and one hepatocellular carcinoma. In two additional cases, patients followed up for a melanoma underwent liver surgery to remove micro nodules possibly related to a metastatic process. Finally in one case a micro nodule was seen and resected during a cholecystectomy.

CONCLUSION

Taken together, H-HCAs are more frequent than we initially supposed as micro and small HCAs cannot all be detected by routine ultrasound. Despite no information on the potential growth of these micro/small H-HCAs, there is no argument to stop oral contraceptives or to ask for a specific regular surveillance. The association of different subtypes of HCAs with focal nodular hyperplasia suggests they share or have common etiological factors.

Hepatocellular Adenomas: Morphology and Genomics

Hepatocellular adenomas (HCAs) are rare benign tumors. This single entity has been split into 3 subtypes corresponding to specific mutations: HNF1α-inactivated HCA; inflammatory HCA related to different mutations, all leading to activation of STAT3 pathway; and β-catenin-activated HCA related to CTNNB1 mutations. The risk of malignant transformation depends on the level of β-catenin activation, reported mainly for exon 3, including S45. It is possible using specific immunohistochemical markers to identify the 3 different HCA subtypes and the level of β-catenin activation. Fewer than 10% of HCAs remain unclassified.

Hepatocellular adenomatosis: what should the term stand for!

In 1985, adenomatosis, a term coined to mean ten or more nodules, was considered as a specific entity different from hepatocellular adenoma (HCA) whether single or multiple. In the 2000s the term has lost its individuality. The great contribution of the classification was to clearly demonstrate that in all hepatocellular subtypes and in particular etiologies such as glycogenosis and male hormone administration, HCA could be solitary, multiple (<10) or multiple (>10: adenomatosis). Management of hepatocellular adenomatosis may not be different from solitary or multiple HCA. To keep its specificity in terms of management and prognosis compared to solitary or multiple HCA, it is necessary to indicate the number of nodules including the combination of three parameters: size, location and subtypes. When the classical armentarium to treat nodules is not possible or too risky, embolization or liver transplantation remains the only therapeutic options.

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/β-catenin and transforming growth factor β 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/β-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.

Pathological Diagnosis of Hepatocellular Cellular Adenoma according to the Clinical Context

In Europe and North America, hepatocellular adenomas (HCA) occur, classically, in middle-aged woman taking oral contraceptives. Twenty percent of women, however, are not exposed to oral contraceptives; HCA can more rarely occur in men, children, and women over 65 years. HCA have been observed in many pathological conditions such as glycogenosis, familial adenomatous polyposis, MODY3, after male hormone administration, and in vascular diseases. Obesity is frequent particularly in inflammatory HCA. The background liver is often normal, but steatosis is a frequent finding particularly in inflammatory HCA. The diagnosis of HCA is more difficult when the background liver is fibrotic, notably in vascular diseases. HCA can be solitary, or multiple or in great number (adenomatosis). When nodules are multiple, they are usually of the same subtype. HNF1 α -inactivated HCA occur almost exclusively in woman. The most important point of the classification is the identification of β -catenin mutated HCA, a strong argument to identify patients at risk of malignant transformation. Some HCA already present criteria indicating malignant transformation. When the whole nodule is a hepatocellular carcinoma, it is extremely difficult to prove that it is the consequence of a former HCA. It is occasionally difficult to identify HCA remodeled by necrosis or hemorrhage.

Hepatocellular adenoma in glycogen storage disorder type I: a clinicopathological and molecular study

AIMS

  Glycogen storage disease type I is a metabolic disorder resulting from deficiency of the glucose-6-phosphate complex. Long-term complications include the development of hepatocellular adenoma (HCA). In this retrospective study, our aim was to reclassify according to geno-phenotypic characteristics nodular lesions identified in hepatectomy specimens of such patients transplanted between 1998 and 2008 at our institution.

METHODS AND RESULTS

  Clinicopathological data of seven consecutive transplanted patients with glycogen storage disease type I were reviewed. Liver nodules were re-examined histologically and by immunohistochemistry. Molecular analysis was performed additionally in a case with specific features. Four patients had multiple tumours. We concluded that 26 of 38 nodules available for study had features of inflammatory hepatocellular adenomas, seven comprised adenomas not otherwise specified and five were found to be focal nodular hyperplasia.

CONCLUSIONS

  Further studies are needed to clarify the pathogenesis of hepatocellular adenomas in glycogen storage disease; in particular to determine whether they share abnormal metabolic pathways with inflammatory adenomas in the general population. Testing for acute phase proteins may be a helpful tool in the early detection of HCA in such patients. Finally, there is a need to further define their risk of malignant transformation, in relation to age and possible cofactors.

Hepatic resection for inflammatory hepatocellular adenomas: pathological identification of micronodules expressing inflammatory proteins

BACKGROUND

Inflammatory hepatocellular adenoma (IHCA) defines a subgroup of hepatocellular adenomas characterized by the expression of members of the acute-phase inflammatory response [(serum amyloid A protein (SAA) and C-reactive protein (CRP)]. IHCA are unique or multiple as defined by the presence of several nodule(s) larger than 10 mm using both imaging and macroscopic observation. Frequently, additional micronodules (<10 mm), previously undetected by imaging, can be observed in resected specimens.

AIMS

To analyse micronodules in multiple (group 1, nine patients) and single (group 2, eight patients) IHCA cases, immunohistochemistry using SAA and CRP antibodies was performed on all nodules detected under macroscopic examination as well as on surrounding tissue with no visible nodules.

RESULTS

Nodules of different sizes (>5 < or = 10 mm, > or = 1 < or = 5 mm) were found in group 1, whereas only rare nodules in the mm range were found in group 2. Micronodules shared the characteristics of large nodules, which justified surgery such as inflammatory infiltrates, abnormal arteries, sinusoidal dilatation or peliosis. However, the number of these characteristics was proportional to the size of the nodules.

CONCLUSION

This study demonstrates that the real number of IHCA is greater than that predicted from imaging-based analyses. In addition, we show that patients with more than one nodule present a greater chance to display more and larger undetected micronodules than patients with a single nodule.

Hepatic adenomatosis

Hepatic adenomatosis was first described in 1985 by Flejou et al as multiple adenomas, arbitrarily more than 10, in an otherwise normal liver parenchyma. Several authors have suggested that it is a distinct entity from hepatic adenoma, which is predominantly seen in young women taking oral contraceptives. Although considered a benign disease, it can be associated with potentially fatal complications such as malignant transformation and intraperitoneal hemorrhage due to rupture. Although its etiology and natural history have not been fully elucidated, germline mutation of hepatocyte nuclear factor 1alpha, which is associated with maturity-onset diabetes of the young type 3, has recently been implicated in a subset of cases. Currently, there is no consensus on patient management. However, surgical removal of large lesions may significantly improve symptoms and reduce the risk of complications. Genetic counseling may now play an important role in case management.

Unexpected discovery of 2 cases of hepatocyte nuclear factor 1α-mutated infracentimetric adenomatosis

We present 2 cases of hepatocyte nuclear factor 1α (HNF1α)-mutated adenomatosis, discovered for reasons unrelated to this disease, and identified using immunohistochemical methods. These new tools may further our understanding of the link between adenomas/adenomatosis subtypes and their complications, and their association with other abnormalities.

Liver adenomatosis: re-evaluation of aetiology and management

BACKGROUND

Liver adenomatosis (LA) is a rare benign parenchymal liver disease with unknown aetiology. In recent reports, LA has been associated with hepatic steatosis, with potential implications for the management of this disease. The aim of this study was to determine prognosis and optimal management of patients with LA.

METHODS

Clinical presentation, diagnostic studies and management of patients with LA were analysed in our centre. Furthermore, a Medline search of all published case reports and series of LA patients was performed.

RESULTS

Ninety-four patients with LA have been reported in the literature. Fifty-two per cent of females had a history of oral contraceptive use. Eighteen per cent of patients had steatosis in nontumoral tissue. In our own series, five of six patients had histologically confirmed steatosis. Forty-three per cent of patients presented with acute pain, of whom 46% had a haemorrhagical complication, in contrast to 2% of nonsymptomatic patients. Tumours <5 cm tended to increase in size during follow-up and only in four patients tumour regression was observed.

CONCLUSION

Liver adenomatosis is a progressive, benign parenchymal disease mainly occurring in females. There is a potential link with hepatic steatosis with implications for the management of patients with LA. Noninvasive diagnosis is difficult because of the variety of tumoral and nontumoral components. Management should primarily be conservative.

Genotype phenotype classification of hepatocellular adenoma

Studies that compare tumor genotype with phenotype have provided the basis of a new histological/molecular classification of hepatocellular adenomas. Based on two molecular criteria (presence of a TCF1/HNF1α or β-catenin mutation), and an additional histological criterion (presence or absence of an inflammatory infiltrate), subgroups of hepatocellular adenoma can be defined and distinguished from focal nodular hyperplasia. Analysis of 96 hepatocellular adenomas performed by a French collaborative network showed that they can be divided into four broad subgroups: the first one is defined by the presence of mutations in TCF1 gene inactivating the hepatocyte nuclear factor 1 (HNF1α); the second by the presence of β-catenin activating mutations; the category without mutations of HNF1α or β-catenin is further divided into 2 subgroups depending on the presence or absence of inflammation. Therefore, the approach to the diagnosis of problematic benign hepatocytic nodules may be entering a new era directed by new molecular information. It is hoped that immunohistological tools will improve significantly diagnosis of liver biopsy in our ability to distinguish hepatocellular adenoma from focal nodular hyperplasia (FNH), and to delineate clinically meaningful entities within each group to define the best clinical management. The optimal care of patients with a liver nodule will benefit from the recent knowledge coming from molecular biology and the combined expertise of hepatologists, pathologists, radiologists, and surgeons.

Hepatocellular adenoma: findings at state-of-the-art magnetic resonance imaging, ultrasound, computed tomography and pathologic analysis

The purpose of this paper is to describe the most recent concepts and pertinent findings of hepatocellular adenomas, including clinical presentation, gross pathology and histology, pathogenesis and transformation into hepatocellular carcinoma (HCC), and imaging findings at ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging.

Familial liver adenomatosis associated with hepatocyte nuclear factor 1alpha inactivation

BACKGROUND & AIMS

Germline mutations in hepatocyte nuclear factor 1alpha (TCF1/HNF-1alpha) are associated with maturity-onset diabetes of the young type 3 (MODY3), and somatic biallelic inactivations of the gene are found in hepatocellular adenomas and liver adenomatosis. This study investigated cosegregation of HNF-1alpha germline mutations with diabetes and liver adenomatosis in 2 families.

METHODS

Two unrelated patients with liver adenomatosis and harboring HNF-1alpha germline and somatic mutations were studied. Subsequently, we screened 9 relatives in the 2 independent families for diabetes, hepatocellular adenomas, and HNF-1alpha germline mutations.

RESULTS

In family A, a father and his son presented with an intraperitoneal hemorrhagic rupture of a liver adenomatosis without diabetes. A heterozygous R229X germline mutation was identified in HNF-1alpha in the father and his son and also in his second 27-year-old son without hepatocellular adenomas. In family B, a diagnosis of liver adenomatosis was made fortuitously in a 14-year-old girl. A heterozygous G55fsX57 germline mutation in HNF-1alpha was identified in this patient, her diabetic father, and her 2 sisters. Systematic exploration showed liver adenomatosis in the 2 sisters. Somatic inactivation of the second HNF-1alpha allele was found in liver tumors in both families.

CONCLUSIONS

This study describes familial liver adenomatosis and shows the association with germline HNF-1alpha mutations in adults and children. It also highlights the importance of screening for hepatocellular adenomas, diabetes, and HNF-1alpha germline mutations in relatives of patients with liver adenomatosis. Finally, prevalence of liver adenomatosis remains to be evaluated in MODY3 subjects.