Natural history of liver adenomatosis: A long-term observational study

Hepatic adenoma: evolution of a more individualized treatment approach

BACKGROUND

Hepatic adenomas (HAs) are benign, solid liver lesions, which carry a risk of hemorrhage and malignant transformation. This review article highlights the advances in the diagnosis and management of HAs.

METHODS

A comprehensive review was performed using MEDLINE/PubMed and Web of Science databases with a search period ending on September 30, 2023. Using PubMed, the terms "hepatocellular," "hepatic," and "adenoma" were searched.

RESULTS

HA has been classified into at least 8 subtypes based on molecular pathology, each exhibiting unique histopathologic features, clinical considerations, and risk of malignant transformation. The most common subtype is inflammatory HA, followed by hepatocyte nuclear factor 1α-inactivated HA, β-catenin exon 3-mutated HA (βex3-HA), β-catenin exon 7- or 8-mutated HA, sonic hedgehog HA, and unclassified HA. Magnetic resonance imaging is the best imaging method for diagnosis and can distinguish among HA subtypes based on fat and telangiectasia pathologic characteristics. The risk of malignant transformation varies among molecular subtypes, ranging from <1% to approximately 50%. Up to 42% of HAs present with spontaneous intratumoral hemorrhage and peritoneal hemorrhage. In general, only 15% to 20% of patients require surgery. HA larger than 5 cm are more likely to be complicated by bleeding and malignant transformation, regardless of subtype, and should generally be resected. In particular, βex3-HA carries a high risk of malignant transformation and can be considered a true precancerous lesion.

CONCLUSION

The management of HAs is based on a multidisciplinary approach. Clinical decision-making should integrate information on gender, tumor size, and HA subtyping. In the future, patients with HA will benefit from novel medical therapies tailored to the individual molecular subtypes.

Hepatic Precancerous Lesions and Early Hepatocellular Carcinoma

This review discusses the diagnostic challenges of diagnosing and treating precursor lesions of hepatocellular carcinoma (HCC) in both cirrhotic and non-cirrhotic livers. The distinction of high-grade dysplastic nodule (the primary precursor lesion in cirrhotic liver) from early HCC is emphasized based on morphologic, immunohistochemical, and genomic features. The risk factors associated with HCC in hepatocellular adenomas (precursor lesion in non-cirrhotic liver) are delineated, and the risk in different subtypes is discussed with emphasis on terminology, diagnosis, and genomic features.

Surgical indications for solid hepatic benign tumors: An updated literature review

Hepatic hemangioma, focal nodular hyperplasia, and hepatic adenoma are the most common benign solid liver tumors. However, their surgical indications have been the subject of debate. Minimally invasive liver resection reduces the cost of surgery and may lead to overtreatment of benign liver tumors. Recently, there has been a growing understanding of the etiology, pathogenesis, and natural history of these tumors. Great progress has also been made in imaging. The use of MRI and contrast agents has improved the accuracy of non-invasive diagnosis of these tumors, and especially in the identification of specific molecular subtypes of liver adenoma. These factors have resulted in alterations of surgical indications for these tumors. This article examines recent literature and it discusses the surgical indications for hepatic hemangioma, focal nodular hyperplasia, and hepatic adenoma while summarizing modifications in clinical management.

Fatal rupture of hepatic adenomatosis: Autopsy case and review of the literature

Hepatic adenomatosis is a rare disease consisting of multiple adenomas in otherwise-normal liver parenchyma. Though the discovery of this entity goes back several years, its diagnosis is still challenging in terms of its definition and pathophysiology. Clinically, patients may be completely asymptomatic and the diagnosis is only made incidentally through imaging tests. The discovery could be made when complications occur such as intraperitoneal hemorrhage with hypovolemic shock due to the rupture of an adenoma. We report a fatal case of a ruptured adenoma in a case of hepatic adenomatosis discovered at autopsy. In order to achieve a better view of this disease, we conducted a literature review on this subject describing the pathogenesis, manifestations, and autopsy contribution to addressing this entity.

Hepatocellular Adenomas: Molecular Basis and Multimodality Imaging Update

Hepatocellular adenomas (HCAs) are a family of liver tumors that are associated with variable prognoses. Since the initial description of these tumors, the classification of HCAs has expanded and now includes eight distinct genotypic subtypes based on molecular analysis findings. These genotypic subtypes have unique derangements in their cellular biologic makeup that determine their clinical course and may allow noninvasive identification of certain subtypes. Multiphasic MRI performed with hepatobiliary contrast agents remains the best method to noninvasively detect, characterize, and monitor HCAs. HCAs are generally hypointense during the hepatobiliary phase; the β-catenin-mutated exon 3 subtype and up to a third of inflammatory HCAs are the exception to this characterization. It is important to understand the appearances of HCAs beyond their depictions at MRI, as these tumors are typically identified with other imaging modalities first. The two most feared related complications are bleeding and malignant transformation to hepatocellular carcinoma, although the risk of these complications depends on tumor size, subtype, and clinical factors. Elective surgical resection is recommended for HCAs that are persistently larger than 5 cm, adenomas of any size in men, and all β-catenin-mutated exon 3 HCAs. Thermal ablation and transarterial embolization are potential alternatives to surgical resection. In the acute setting of a ruptured HCA, patients typically undergo transarterial embolization with or without delayed surgical resection. This update on HCAs includes a review of radiologic-pathologic correlations by subtype and imaging modality, related complications, and management recommendations. ^© RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Benign liver lesions 2022: Guideline for clinical practice of Associazione Italiana Studio del Fegato (AISF), Società Italiana di Radiologia Medica e Interventistica (SIRM), Società Italiana di Chirurgia (SIC), Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB), Associazione Italiana di Chirurgia Epatobilio-Pancreatica (AICEP), Società Italiana Trapianti d'Organo (SITO), Società Italiana di Anatomia Patologica e Citologia Diagnostica (SIAPEC-IAP) - Part II - Solid lesions

Benign liver lesions are increasingly diagnosed in daily clinical practice due to the growing use of imaging techniques for the study of the abdomen in patients who have non-specific symptoms and do not have an increased risk of hepatic malignancy. They include simple or parasitic hepatic cysts and solid benign tumors which differ widely in terms of prevalence, clinical relevance, symptoms and natural history and often lead to significant clinical problems relating to diagnosis and clinical management. Following the need to have updated guidelines on the management of benign focal liver lesions, the Scientific Societies mainly involved in their management have promoted the drafting of a new dedicated document. This document was drawn up according to the present Italian rules and methodologies necessary to produce clinical, diagnostic, and therapeutic guidelines based on evidence. Here we present the second part of the guideline, concerning the diagnosis and clinical management of hemangioma, focal nodular hyperplasia, and hepatocellular adenoma.

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.

Large Hepatic Adenomas and Hepatic Adenomatosis: A Multicenter Study of Risk Factors, Interventions, and Complications

INTRODUCTION

Beyond oral contraceptives (OCs), metabolic factors have been suggested to increase the risk of hepatocellular adenoma (HCA). The impact of risks remains poorly defined, particularly among men and those with adenomatosis. Thus, we aimed to examine HCA clinical and outcome characteristics through a large multicenter cohort.

METHODS

HCA diagnosis was made based on a combination of clinical, radiologic, and histologic criteria. Patient and clinical data including follow-up imaging, complications, and interventions were collected between 2004 and 2018 from 3 large academic centers.

RESULTS

Among 187 patients (163 female and 24 male) with HCA, 75 had solitary HCA, 58 had multiple HCAs, and 54 had adenomatosis. Over a median follow-up of 3.3 years (quartile 1: 1.2, quartile 3: 8.8), 34 patients (18%) had radiologic interventions, 41 (21%) had surgical resections, 10 (5%) developed tumoral hemorrhage, and 1 had malignant transformation. OC and corticosteroid use were present in 70% and 16%, respectively. Obesity (51%), type 2 diabetes (24%), hypertension (42%), and hypertriglyceridemia (21%) were also common. Metabolic comorbidities were more common in patients with large HCAs and adenomatosis. Compared with women, men had less hepatic steatosis (4% vs 27%), smaller HCAs (2.3 cm vs 4.4 cm), and more corticosteroid use (38% vs 11%) ( P < 0.05 for all). With OC cessation, 69% had a decrease in size of HCA, but 25% eventually required advanced interventions.

DISCUSSION

In this large HCA cohort, obesity and metabolic comorbidities were important risk factors associated with large HCAs and adenomatosis. Long-term adverse outcomes were infrequent, 5% had tumor hemorrhage, and 1 patient exhibited malignant transformation.

A Scoping Review of the Classification, Diagnosis, and Management of Hepatic Adenomas

BACKGROUND

Hepatic adenomas (HA), or hepatocellular adenomas, are benign, solid liver lesions that develop in otherwise normal livers, often in the setting of increased estrogen levels. While considered a benign tumor, there is a risk for substantial complications such as hemorrhage and malignant transformation. We review the diagnosis, classification, and potential therapeutic management options for patients with HA.

METHODS

A scoping narrative review was conducted based on recent literature regarding classification, diagnosis, and management of HA.

RESULTS

While HAs are typically considered benign, complications such as hemorrhage and malignant transformation may occur in approximately 25% and 5% of patients, respectively. Recent advances in imaging and molecular profiling have allowed for the classification of HAs into subtypes allowing for patient risk stratification that helps guide management. Surgical resection should be considered in asymptomatic patients who are male, have an adenoma ≥5 cm in diameter, or have the β-catenin-activated subtype due to an increased risk of hemorrhage and/or malignant transformation.

CONCLUSION

Molecular profiling has aided in the stratification of patients relative to the risk of complications to predict better the potential behavior of HAs.

An Extreme Case of Liver Adenomatosis: Are They All the Same?

Hepatocellular adenoma (HCA) is a rare and benign liver tumor that affects predominantly young and middle-aged women, especially between 30–40 years old. Liver adenomatosis (LA) is defined as the presence of 10 or more HCA. There are authors that report eight different subtypes of HCA, that correlates with clinical and histopathological features, being the inflammatory subtype the most common. We present a case of a 32-year-old Caucasian woman with a history of self-limited episodes of right abdominal pain and an abdominal ultrasound with multiple hypoechogenic liver nodules, suspected of metastasis. She was taking combined oral contraceptive for 6 years. Magnetic Resonance Imaging (MRI) disclosed around 40 nodules, suggestive of HCA. Liver biopsy confirmed HCA, inflammatory subtype. Oral contraceptive was stopped and control MRI 6 months later disclosed reduction of nodules’ dimensions. Management of patients with LA should be based on the size of the largest tumor, as clinical presentation and risk of bleeding or malignancy do not differ between patients with single or multiple HCAs. However, even with biopsy, there is a risk of missampling, raising concern about the real risk of bleeding and malignant potential in patients with different subtypes coexisting in the same liver.

Liver Transplantation for Hepatic Adenoma: A UNOS Database Analysis and Systematic Review of the Literature

BACKGROUND

Liver transplantation (LT) has been employed for hepatic adenoma (HA) on a case-oriented basis. We aimed to describe the characteristics, waitlist, and post-LT outcomes of patients requiring LT for HA.

METHODS

All patients listed or transplanted for HA in the United States were identified in the United Network for Organ Sharing (UNOS) database (1987-2020). A systematic literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement.

RESULTS

A total of 199 HA patients were listed for LT in UNOS and the crude waitlist mortality was 9.0%. A total of 142 HA patients underwent LT; 118 of these were among those listed with an indication of HA who underwent LT, and 24 were diagnosed incidentally. Most did not experience hepatocellular carcinoma transformation (89.4%). Over a median follow-up of 62.9 mo, death was reported in 18.3%. The 1-, 3-, and 5-y patient survival rates were 94.2%, 89.7%, and 86.3% in the UNOS cohort. The systematic review yielded 61 articles reporting on 99 nonoverlapping patients undergoing LT for HA and 2 articles reporting on multicenter studies. The most common LT indications were suspected malignancy (39.7%), unresectable HA (31.7%), and increasing size (27.0%), whereas 53.1% had glycogen storage disease. Over a median follow-up of 36.5 mo, death was reported in 6.0% (n=5/84). The 1-, 3-, and 5-y patient survival rates were all 95.0% in the systematic review.

CONCLUSIONS

LT for HA can lead to excellent long-term outcomes in well-selected patients. Prospective granular data are needed to develop more optimal selection criteria and further improve outcomes.

Risk factors for bleeding hepatocellular adenoma in a United States cohort

BACKGROUND & AIMS

Known risk factors for hepatocellular adenoma (HCA) bleeding are size >5 cm, growth rate, visible vascularity, exophytic lesions, β-catenin and Sonic Hedgehog activated HCAs. Most studies are based on European cohorts. The objective of this study is to identify additional risk factors for HCA bleeding in a US cohort.

METHODS

Retrospective chart review was performed on patients diagnosed with HCA on magnetic resonance imaging (n = 184) at an academic tertiary institution. Clinical, pathological, and imaging data were collected. Primary outcomes measured were HCA bleeding and malignancy. Statistical analysis was performed with SAS 9.4 using Chi-Square, Fisher's exact test, sample t test, non-parametric Wilcoxon test, and logistic regression.

RESULTS

After excluding patients whose pathology showed focal nodular hyperplasia and non-adenoma lesions, follow-up data were available for 167 patients. 16% experienced microscopic or macroscopic bleeding and 1.2% had malignancy. HCA size predicted bleeding (P < .0001) and no patients with lesion size <1.8 cm bled. In unadjusted analysis, hepatic adenomatosis (≥10 lesions) trended towards 2.8-fold increased risk of bleeding. Of patients with a single lesion that bled, 77% bled from a lesion >5 cm. In patients with multiple HCAs that bled, 50% bled from lesions <5 cm. In patients with multiple adenomas, size (P = .001) independently predicted bleeding and hepatic steatosis trended towards increased risk of bleeding (P = .05).

CONCLUSIONS

In a large US cohort, size predicted increased risk of HCA bleeding while hepatic adenomatosis trended towards increased risk of bleeding. In patients with multiple HCAs, size predicted bleeding and hepatic steatosis trended toward increased risk of bleeding.

Case Report: Hepatic Adenomatosis in a Patient With Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a genetic disorder caused by the lack of expression of genes on the paternally inherited chromosome region 15q11.2-q13. It is a multisystem disorder that is characterized by severe hypotonia with poor suck and feeding difficulties in early infancy, followed in early childhood by excessive eating and gradual development of morbid obesity. The incidence of type 2 diabetes mellitus is high, particularly in obese patients. Non-alcoholic fatty liver disease has also been reported in some patients with PWS. Liver adenomatosis is a benign vascular lesion of the liver, defined by the presence of >10 adenomas, in the otherwise healthy liver parenchyma. We report the first case of a patient with PWS with severe obesity, type 2 diabetes mellitus, and non-alcoholic fatty liver who also developed liver adenomatosis, review the pediatric literature on liver adenomatosis, and discuss the potential underlying mechanisms.

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.

Hepatic adenomatosis in a young woman with non-familial maturity-onset diabetes of the young type 3

Hepatic adenomatosis (HA) is a rare condition in which multiple adenomas exist in an otherwise healthy liver. The most common subtype (H-HA) is associated with bi-allelic, somatic hepatic nuclear factor 1-alpha (HNF1A) mutations. Maturity-onset diabetes of the young type 3 (MODY3) is most often seen in young individuals with heterozygous, germline mutations in HNF1A. In this report, we describe a 17-year-old woman with H-HA and non-familial MODY3.

Behavior and complications of hepatocellular adenoma during pregnancy and puerperium: a retrospective study and systematic review

BACKGROUND

Hepatocellular adenomas (HCA) are benign liver tumors at risk of hemorrhage. The influence of pregnancy on HCA growth and potential bleeding remains unclear. This study investigates HCA-associated behavior and bleeding complications during or shortly after pregnancy.

METHODS

(I) Single center retrospective cohort study of HCA during and after pregnancy (II) Systematic literature review.

RESULTS

The retrospective study included 11 patients, of which 4 with HCA ≥5 cm. In only two patients HCA showed growth during pregnancy. In this local cohort, no HCA-related hemorrhages occurred during median follow-up of 34 months (interquartile range 19-58 months). The systematic review yielded 33 studies, totaling 90 patients with 99 pregnancies. Of 73 pregnancies without prior HCA-related intervention, 39 HCA remained stable (53.4%), 11 regressed (15.1%), and 23 (31.5%) progressed. Fifteen HCA-related hemorrhages occurred in HCA measuring 6.5-17.0 cm. Eight patients experienced bleeding during pregnancy, two during labor and five postpartum.

CONCLUSION

Although hemorrhage of HCA during or shortly after pregnancy is rare and only reported in HCA ≥6.5 cm, it can be fatal. Pregnancy in women with HCA, regardless of size, warrant a close surveillance strategy. Observational studies on behavior and management of HCA ≥5 cm during and immediately after pregnancy are needed.

Diagnostic value of morphological enhancement patterns in the hepatobiliary phase of gadoxetic acid-enhanced MRI to distinguish focal nodular hyperplasia from hepatocellular adenoma

OBJECTIVES

To describe the different morphological enhancement patterns of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI (Gd-EOB-DTPA MRI) and to determine their added value in their differential diagnosis.

METHODS

A retrospective analysis of imaging findings in 185 benign hepatocellular lesions (154 FNH; 31 HCA) in 108 patients who underwent Gd-EOB-DTPA MRI was performed by two independent reviewers. Six patterns on HBP were recorded: 1) homogeneous enhancement; 2) peripheral ring-like enhancement with hypointense central core; 3) peripheral ring-like enhancement with hyperintense central core; 4) central core enhancement with hypointense periphery; 5) heterogeneous enhancement; and 6) the absence of enhancement.

RESULTS

Peripheral ring-like enhancement with hypointense central core and peripheral ring-like enhancement with hyperintense central core showed the highest specificity for the diagnosis of FNH (100% and 96.8%, respectively). The absence of enhancement and central core enhancement with hypointense periphery were only present in 0.6% and 1.9% of FHN, respectively. All other patterns were observed with similar frequencies in FNH (22.1% to 26.6%). Six HCA showed contrast uptake on the HBP: homogeneous (6.5%), peripheral ring-like enhancement with hyperintense central core (3.2%) and heterogeneous (9.7%).

CONCLUSION

Both FNH and HCA may demonstrate enhancement in the HBP of Gd-EOB-DTPA MRI, limiting its specificity. A significant improvement in specificity can be achieved by the evaluation of morphological enhancement patterns: Peripheral ring-like enhancement with hypointense or hyperintense central core was highly specific for FNH diagnosis. On the other hand, the absence of HBP enhancement makes the diagnosis of FNH unlikely.

Regression of multiple hepatocellular adenomas after cessation of oral contraceptive pills: a case report and review of the current literature

Hepatocellular adenoma (HCA) is an uncommon benign liver neoplasm usually solitary and identified incidentally on imaging. We report a case of a 50-year old female who was diagnosed with multiple hepatic adenomas of the inflammatory subtype. After discontinuation of oral contraception a decrease of both the number and size of the liver lesions was seen on magnetic resonance imaging (MRI) without the need of further intervention. The major challenge in the clinical management of patients with multiple HCAs resides in the risk assessment for future complications. In the case of multiple HCAs subtype seemed to be more relevant than the actual number of lesions. Because little is known about the natural evolution in patients with multiple HCAs, we performed a review of the current literature with focus on the different subtypes and their clinical relevance.

Malignant Transformation of an HNF1a-Inactivated Hepatocellular Adenoma to Hepatocellular Carcinoma

Hepatocellular adenomas (HCA) are rare benign tumors of the liver, occurring predominantly in females using oral contraceptives. Our case describes a 66-year-old woman presenting with a palpable mass in her upper abdomen. Contrast-enhanced computed tomography and magnetic resonance imaging showed a large exophytic mass protruding from the caudal border of liver segments IV and V, without visible metastases. Laparoscopic resection of the tumor and gallbladder was performed. Histopathological examination showed a hepatocellular carcinoma with areas of HNF1a-HCA (H-HCA). This case shows that malignant transformation is possible in H-HCA. We present our preoperative decision-making process, as well as the role of imaging techniques in this rare case.

A multicentre retrospective analysis on growth of residual hepatocellular adenoma after resection

BACKGROUND & AIMS

Hepatocellular adenoma (HCA) is a benign liver tumour that may require resection in select cases. The aim of this study was to the assess growth of residual HCA in the remnant liver and to advise on an evidence-based management strategy.

METHOD

This multicentre retrospective cohort study included all patients with HCA who underwent surgery of HCA and had residual HCA in the remnant liver. Growth was defined as an increase of >20% in transverse diameter (RECIST criteria). Data on patient and HCA characteristics, diagnostic work-up, treatment and follow-up were documented and analysed.

RESULTS

A total of 134 patients were included, one male. At diagnosis, median age was 38yrs (IQR 30.0-44.0) and median BMI was 29.9 kg/m² (IQR 24.6-33.3). After resection, median number of residual sites of HCA was 3 (IQR 2-6). Follow-up of residual HCA showed regression in 24.6%, stable HCA in 61.9% and growth of at least one lesion in 11.2%. Three patients (2.2%) developed new HCA that were not visible on imaging prior to surgery. Four patients (3%, one male) underwent an intervention as growth was progressive. No statistically significant differences in clinical characteristics were found between patients with growing residual or new HCA versus those with stable or regressing residual HCA.

CONCLUSION

In patients with multiple HCA who undergo resection, growth of residual HCA is not uncommon but interventions are rarely needed as most lesions stabilize and do not show progressive growth. Surveillance is indicated when residual HCA show growth after resection, enabling intervention in case of progressive growth.

New insights in the management of Hepatocellular Adenoma

Hepatocellular adenoma (HCA) are benign liver tumours that may be complicated by haemorrhage or malignant transformation to hepatocellular carcinoma. Epidemiological data are fairly outdated, but it is likely to assume that the incidence has increased over the past decades as HCA are more often incidentally found due to the more widespread use of imaging techniques and the increased incidence of obesity. Various molecular subgroups have been described. Each of these molecular subgroups are defined by specific gene mutations and pathway activations. Additionally, they are all related to specific risk factors and show a various biological behaviour. These molecular subgroups may be identified using immunohistochemistry and molecular characterization. Contrast-enhanced MRI is the recommended imaging modality to analyse patients with suspected hepatocellular adenoma allowing to determine the subtype in up to 80%. Surgical resection remains to be the golden standard in treating HCA, although resection is deemed unnecessary in a large number of cases, as studies have shown that the majority of HCA will regress over time without complications such as haemorrhage or malignant transformation occurring. It is preferable to treat patients with suspected HCA in high volume centres with combined expertise of liver surgeons, hepatologists, radiologists and (molecular) pathologists.

[Management of benign liver tumors]

Benign liver tumors form a heterogeneous group. The most frequent forms include simple cysts, hemangiomas, focal nodular hyperplasia and hepatocellular adenomas. They are often incidentally detected during routine sonography. The diagnosis of a liver tumor not uncommonly causes anxiety and insecurity in those affected, which is why a rapid and reliable diagnostic procedure should be carried out. Because some tumors, particularly hepatocellular adenomas, are of prognostic relevance due to the potential risk of malignant transformation, a correct classification should always be strived for. The type and extent of diagnostic clarification depend on the clinical and patient-related risk factors. This article describes the most important benign space-occupying lesions. The etiology, clinical manifestations and diagnostics as well as possible necessary treatment measures are presented.

Diagnosis of hepatocellular adenoma in men before onset of diabetes in HNF1A-MODY: Watch out for winkers

Hepatocyte nuclear factor 1A (HNF1A) maturity-onset diabetes of the young (MODY) is a monogenetic, autosomal dominantly inherited form of diabetes. HNF1A-MODY is associated with HNF1A-inactivated hepatocellular adenoma (H-HCA) formation. Hepatocellular adenoma (HCA) are benign liver tumours and related complications are rare but serious: hepatic haemorrhage and malignant transformation. Guidelines recommend resection of all HCA in men and do not take any co-occurring metabolic disorders into account. We report a family with HCA preceding diabetes mellitus. Male index patient presented with numerous, irresectable HCA. After initial diagnostic and aetiologic uncertainty HNF1A germline mutation c.815G>A (p.Arg272His) was confirmed 8 years later. No HCA-related complications occurred. His diabetic mother was diagnosed with HCA after severe hepatic haemorrhage years before. HNF1A-MODY should be considered in (non-)diabetic (male) patients with H-HCA. We advocate liver biopsy and, if necessary, genetic analysis to precede any intervention for HCA in males and screening for HCA in HNF1A-MODY patients.