Systematic review of haemorrhage and rupture of hepatocellular adenomas

Sonic hedgehog hepatocellular adenoma: magnetic resonance imaging features and correlation with histology

OBJECTIVES

Sonic hedgehog hepatocellular adenoma (shHCA) is a new hepatocellular adenoma (HCA) subgroup characterized by high risk of hemorrhage. ShHCA account for below 10% of all HCA cases and are often associated with female gender, obesity, and non-alcoholic steatohepatitis. No specific MRI characteristics have been described to date. The objective of this study was to assess the value of using MRI to identify shHCA, and correlate MRI findings with histology.

METHODS

We retrospectively collected MRI scans of 29 patients with shHCA from our center and from different liver referral centers to include 35 lesions. Diagnosis of shHCA was assessed by immunohistochemical overexpression of argininosuccinate synthase 1 or prostaglandin D2 synthase, then confirmed by molecular analysis of sonic hedgehog pathway activation and/or by proteomic analysis.

RESULTS

In 46% (n = 16/35) of shHCA cases, we detected intralesional fluid-filled cavities defined on MR images as fluid-like foci markedly hyperintense on T2-weighted sequences, and hypointense on T1-weighted sequences, with or without delayed enhancement. Pathologically, these cavities were observed in 54% of cases as vacuoles filled with blood at different stages of degradation. Hemorrhage and/or necrosis were detected among 71% of cases by MRI analysis (n = 25/35) versus 82% pathologically. Seventeen percent of shHCA cases (n = 6/35) were completely homogeneous via MRI and pathological analysis. No MRI criteria was found in favor of focal nodular hyperplasia, HNF1A-mutated HCA, or typical inflammatory HCA.

CONCLUSION

We reveal the presence of intralesional fluid-filled cavities among 46% of our shHCA cases that represent a new MRI finding possibly helpful for shHCA diagnosis.

CLINICAL RELEVANCE STATEMENT

This multicenter study is the first clinical study about the radiological aspect of this new hepatocellular adenoma subgroup. This highlights a strong correlation between MRI and histological analysis, with a specific pattern emerging for diagnosis.

KEY POINTS

• Sonic hedgehog hepatocellular adenoma is a new hepatocellular adenoma subgroup associated with high risk of hemorrhage, but imaging features of this subgroup remain unknown. • Analysis of MR images and correlation with pathology revealed intralesional fluid-filled cavities and necrotic-hemorrhagic changes. • Intralesional fluid-filled cavities have not yet been described in other adenoma subtypes and represent a new MRI finding for sonic hedgehog hepatocellular adenoma.

Imaging features and management of focal liver lesions

Notably, the number of incidentally detected focal liver lesions (FLLs) has increased dramatically in recent years due to the increased use of radiological imaging. The diagnosis of FLLs can be made through a well-documented medical history, physical examination, laboratory tests, and appropriate imaging methods. Although benign FLLs are more common than malignant ones in adults, even in patients with primary malignancy, accurate diagnosis of incidental FLLs is of utmost clinical significance. In clinical practice, FLLs are frequently evaluated non-invasively using ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Although US is a cost-effective and widely used imaging method, its diagnostic specificity and sensitivity for FLL characterization are limited. FLLs are primarily characterized by obtaining enhancement patterns through dynamic contrast-enhanced CT and MRI. MRI is a problem-solving method with high specificity and sensitivity, commonly used for the evaluation of FLLs that cannot be characterized by US or CT. Recent technical advancements in MRI, along with the use of hepatobiliary-specific MRI contrast agents, have significantly improved the success of FLL characterization and reduced unnecessary biopsies. The American College of Radiology (ACR) appropriateness criteria are evidence-based recommendations intended to assist clinicians in selecting the optimal imaging or treatment option for their patients. ACR Appropriateness Criteria Liver Lesion-Initial Characterization guideline provides recommendations for the imaging methods that should be used for the characterization of incidentally detected FLLs in various clinical scenarios. The American College of Gastroenterology (ACG) Clinical Guideline offers evidence-based recommendations for both the diagnosis and management of FLL. American Association for the Study of Liver Diseases (AASLD) Practice Guidance provides an approach to the diagnosis and management of patients with hepatocellular carcinoma. In this article, FLLs are reviewed with a comprehensive analysis of ACR Appropriateness Criteria, ACG Clinical Guideline, AASLD Practice Guidance, and current medical literature from peer-reviewed journals. The article includes a discussion of imaging methods used for the assessment of FLL, current recommended imaging techniques, innovations in liver imaging, contrast agents, imaging features of common nonmetastatic benign and malignant FLL, as well as current management recommendations.

Lesions hyper- to isointense to surrounding liver in the hepatobiliary phase of gadoxetic acid-enhanced MRI

OBJECTIVES

Hyper- or isointensity in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI has high specificity for focal nodular hyperplasia (FNH) but may be present in hepatocellular adenoma and carcinoma (HCA/HCC). This study aimed to identify imaging characteristics differentiating FNH and HCA/HCC.

MATERIALS AND METHODS

This multicenter retrospective cohort study included patients with pathology-proven FNH or HCA/HCC, hyper-/isointense in the HBP of gadoxetic acid-enhanced MRI between 2010 and 2020. Diagnostic performance of imaging characteristics for the differentiation between FNH and HCA/HCC were reported. Univariable analyses, multivariable logistic regression analyses, and classification and regression tree (CART) analyses were conducted. Sensitivity analyses evaluated imaging characteristics of B-catenin-activated HCA.

RESULTS

In total, 124 patients (mean age 40 years, standard deviation 10 years, 108 female) with 128 hyper-/isointense lesions were included. Pathology diagnoses were FNH and HCA/HCC in 64 lesions (50%) and HCA/HCC in 64 lesions (50%). Imaging characteristics observed exclusively in HCA/HCC were raster and atoll fingerprint patterns in the HBP, sinusoidal dilatation on T2-w, hemosiderin, T1-w in-phase hyperintensity, venous washout, and nodule-in-nodule partification in the HBP and T2-w. Multivariable logistic regression and CART additionally found a T2-w scar indicating FNH, less than 50% fat, and a spherical contour indicating HCA/HCC. In our selected cohort, 14/48 (29%) of HCA were B-catenin activated, most (13/14) showed extensive hyper-/isointensity, and some had a T2-w scar (4/14, 29%).

CONCLUSION

If the aforementioned characteristics typical for HCA/HCC are encountered in lesions extensively hyper- to isointense, further investigation may be warranted to exclude B-catenin-activated HCA.

CLINICAL RELEVANCE

Hyper- or isointensity in the HBP of gadoxetic acid-enhanced MRI is specific for FNH, but HCA/HCC can also exhibit this feature. Therefore, we described imaging patterns to differentiate these entities.

KEY POINTS

FNH and HCA/HCC have similar HBP intensities but have different malignant potentials. Six imaging patterns exclusive to HCA/HCC were identified in this lesion population. These features in liver lesions hyper- to isointense in the HBP warrant further evaluation.

Progestins as a Contributing Factor to Hepatocellular Adenoma: A Case Series and Literature Review

STUDY OBJECTIVE

To explore the role of progestins as potential contributing factors for the development of hepatocellular adenoma (HA) METHODS: We describe 3 cases of adolescents and young adults who developed HA while on norethindrone (NET), as well as their management. In addition, we provide a comprehensive literature review on the association between progestins and HA.

RESULTS

Since 1983, 16 cases of HA in patients on progestins have been reported. Ten patients were on NET and 5 on a prodrug of NET (4 on norethindrone acetate [NETA] and 1 on lynestrenol). One individual had a norgestrel implant. Eight subsequently ceased all hormones: 4 experienced a size reduction, and 3 had complete resolution of their HA. Among our patients, 1 ceased NET and instead had a levonorgestrel intrauterine device inserted, and another swapped from NET to oral medroxyprogesterone acetate. Both experienced complete resolution of their HA. The third ceased NET and underwent a hysterectomy, with size reduction of her HA.

CONCLUSION

These cases and the literature review suggest an association between progestin exposure, in particular NET and its prodrugs, and the development of HA. The pathophysiology is unknown but may include peripheral conversion of NET and NETA to ethinyl estradiol or a specific action of 19-nortestosterone derivatives on hepatocytes, especially those with higher systemic doses compared with the levonorgestrel intrauterine device. There are no case reports relating to other forms of progestins, such as 17-hydroxyprogesterone, which may be important when considering alternative therapeutic options in females requiring effective menstrual management who have comorbidities.

Spatial characterisation of β-catenin-mutated hepatocellular adenoma subtypes by proteomic profiling of the tumour rim

Background & Aims

Hepatocellular adenomas (HCAs) are rare, benign, liver tumours classified at the clinicopathological, genetic, and proteomic levels. The β-catenin-activated (b-HCA) subtypes harbour several mutation types in the β-catenin gene (CTNNB1) associated with different risks of malignant transformation or bleeding. Glutamine synthetase is a surrogate marker of β-catenin pathway activation associated with the risk of malignant transformation. Recently, we revealed an overexpression of glutamine synthetase in the rims of exon 3 S45-mutated b-HCA and exon 7/8-mutated b-HCA compared with the rest of the tumour. A difference in vascularisation was found in this rim shown by diffuse CD34 staining only at the tumour centre. Here, we aimed to characterise this tumour heterogeneity to better understand its physiopathological involvement.

Methods

Using mass spectrometry imaging, genetic, and proteomic analyses combined with laser capture microdissection, we compared the tumour centre with the tumour rim and with adjacent non-tumoural tissue.

Results

The tumour rim harboured the same mutation as the tumour centre, meaning both parts belong to the same tumour. Mass spectrometry imaging showed different spectral profiles between the rim and the tumour centre. Proteomic profiling revealed the significant differential expression of 40 proteins at the rim compared with the tumour centre. The majority of these proteins were associated with metabolism, with an expression profile comparable with a normal perivenous hepatocyte expression profile.

Conclusions

The difference in phenotype between the tumour centres and tumour rims of exon 3 S45-mutated b-HCA and exon 7/8-mutated b-HCA does not depend on CTNNB1 mutational status. In a context of sinusoidal arterial pathology, tumour heterogeneity at the rim harbours perivenous characteristics and could be caused by a functional peripheral venous drainage.

Impact and implications

Tumour heterogeneity was revealed in β-catenin-mutated hepatocellular adenomas (b-HCAs) via the differential expression of glutamine synthase at tumour rims. The combination of several spatial approaches (mass spectrometry imaging, genetic, and proteomic analyses) after laser capture microdissection allowed identification of a potential role for peripheral venous drainage underlying this difference. Through this study, we were able to illustrate that beyond a mutational context, many factors can downstream regulate gene expression and contribute to different clinicopathological phenotypes. We believe that the combinations of spatial analyses that we used could be inspiring for all researchers wanting to access heterogeneity information of liver tumours.

Ancillary tests for hepatobiliary neoplasms: what we know and what we need to know

Ancillary tests are commonly used in the surgical pathology setting for diagnosing challenging neoplastic diseases of the liver and biliary tract, while histology and clinical correlation remain to be critically important. With continuous discoveries, more and more useful ancillary tests have become available, which can help distinguish between malignant and benign hepatocellular neoplasms, malignant and benign biliary tract entities, and intrahepatic and metastatic carcinomas. This review will focus on existing and emerging biomarkers (such as glutamine synthetase, organic anion transporting polypeptide 1B3, insulin-like growth factor-II mRNA binding protein-3, S100P, SMAD4, enhancer of zeste homolog 2, albumin, hepatocyte nuclear factor-1β, etc.) that can be used for the diagnosis, classification and prognostication of hepatobiliary neoplasms.

Bleeding hepatocellular adenoma: historical series and outcomes

INTRODUCTION

hepatocellular adenoma - AHC - is a rare benign neoplasm of the liver more prevalent in women at reproductive age and its main complication is hemorrhage. In the literature, case series addressing this complication are limited.

METHODS

between 2010 and 2022, 12 cases of bleeding AHC were attended in a high-complexity university hospital in southern Brazil, whose medical records were retrospectively evaluated.

RESULTS

all patients were female, with a mean age of 32 years and a BMI of 33kg/m2. The use of oral contraceptives was identified in half of the sample and also half of the patients had a single lesion. The mean diameter of the largest lesion was 9.60cm and the largest lesion was responsible for bleeding in all cases. The presence of hemoperitoneum was documented in 33% of the patients and their age was significantly higher than the patients who did not have hemoperitoneum - 38 vs 30 years, respectively. Surgical resection of the bleeding lesion was performed in 50% of the patients and the median number of days between bleeding and resection was 27 days. In only one case, embolization was used. The relation between ingrowth of the lesions and the time, in months, was not obtained in this study.

CONCLUSION

it is concluded that the bleeding AHC of the present series shows epidemiological agreement with the literature and may suggest that older patients trend to have hemoperitoneum more frequently, a fact that should be investigated in further studies.

A Case Report on a Giant Hepatic Inflammatory Adenoma in a Young Female That Presented as Spontaneous Intrahepatic Hematoma

Among the extensive variety of disorders that can cause acute abdominal pain are hepatocellular adenomas (HCAs), pathological entities that otherwise are asymptomatic. Here, we describe a 33-year-old female who presented in the emergency department with acute abdominal pain and a history of liver focal nodular hyperplasia (FNH) diagnosed 10 years ago. An abdominal magnetic resonance imaging (MRI) revealed that the cause of the pain was an intrahepatic hematoma. The mass was surgically removed, and the biopsy revealed inflammatory adenomas, a subtype of HCA. Hepatic adenoma diagnosis remains challenging by clinical and imaging techniques, and usually, a biopsy is the main diagnostic tool. HCA should be differentiated from hepatocellular carcinoma (HCC), FNH, hepatic angioleiomyoma, and hepatic hemangioma. In our case, HCA was misdiagnosed in the past as FNH. HCA rarely may present as acute right abdomen pain, and a potential catastrophic hemorrhage or rupture must be excluded.

[Benign solid liver tumors]

Benign solid liver tumors are frequently discovered during routine sonographic examinations. As a rule, malignant tumors can be excluded using contrast medium-based sectional imaging; however, unclear cases can represent a diagnostic challenge. The category of solid benign liver tumors includes first and foremost hepatocellular adenoma (HCA), focal nodular hyperplasia (FNH) and hemangioma. Based on the most recent data, an overview of the current standards in the diagnostics and treatment is given.

Body weight changes and duration of estrogen exposure modulate the evolution of hepatocellular adenomas after contraception discontinuation

BACKGROUND AND AIMS

The natural history of hepatocellular adenomas (HCAs) remains to be better described, especially in nonresected patients. We aim to identify the predictive factors of HCA evolution after estrogen-based contraception discontinuation.

APPROACH AND RESULTS

We retrospectively included patients with a histological diagnosis of HCA from three centers. Clinical, radiological, and pathological data were collected to identify predictive factors of radiological evolution per Response Evaluation Criteria in Solid Tumors, version 1.1, and occurrence of complications (bleeding, malignant transformation). We built a score using variables that modulate estrogen levels: body mass index and duration of estrogen-based contraception. An external cohort was used to validate this score. 183 patients were included in the cohort, including 161 women (89%) using estrogen-based contraception for a median of 12 years. Thirty percent of patients had at least one HNF1A -inactivated HCA, 45.5% at least one inflammatory HCA, and 11% at least one HCA with activation of β-catenin (bHCA). Twenty-one symptomatic bleedings (11%) and eleven malignant transformations (6%) occurred. Ages < 37 years old ( p = 0.004) and HCA > 5 cm at imaging were independently associated with symptomatic bleeding ( p = 0.003), whereas a bHCA was associated with malignant transformation ( p < 0.001). After a median follow-up of 5 years, radiological regression was observed in 31%, stabilization in 47%, and progression in 22% of patients. Weight loss was associated with regression ( p < 0.0001) and weight gain with progression ( p = 0.02). The estrogen exposure score predicted radiological regression (odds ratio, 2.33; confidence interval 95%, 1.29-4.19; p = 0.005) with a linear relationship between the rate of estrogen exposure and the probability of regression. This result was confirmed in an external cohort of 72 female patients ( p = 0.003).

CONCLUSION

Weight variation is strongly associated with radiological evolution after oral contraception discontinuation. A score of estrogen exposure, easily assessable in clinical practice at diagnosis, predicts regression of HCA.

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.

Focal Nodular Hyperplasia and Focal Nodular Hyperplasia-like Lesions

Focal nodular hyperplasia (FNH) is a benign lesion occurring in a background of normal liver. FNH is seen most commonly in young women and can often be accurately diagnosed at imaging, including CT, MRI, or contrast-enhanced US. In the normal liver, FNH frequently must be differentiated from hepatocellular adenoma, which although benign, is managed differently because of the risks of hemorrhage and malignant transformation. When lesions that are histologically identical to FNH occur in a background of abnormal liver, they are termed FNH-like lesions. These lesions can be a source of diagnostic confusion and must be differentiated from malignancies. Radiologists' familiarity with the imaging appearance of FNH-like lesions and knowledge of the conditions that predispose a patient to their formation are critical to minimizing the risks of unnecessary intervention for these lesions, which are rarely symptomatic and carry no risk for malignant transformation. FNH is thought to form secondary to an underlying vascular disturbance, a theory supported by the predilection for formation of FNH-like lesions in patients with a variety of hepatic vascular abnormalities. These include abnormalities of hepatic outflow such as Budd-Chiari syndrome, abnormalities of hepatic inflow such as congenital absence of the portal vein, and hepatic microvascular disturbances, such as those that occur after exposure to certain chemotherapeutic agents. Familiarity with the imaging appearances of these varied conditions and knowledge of their association with formation of FNH-like lesions allow radiologists to identify with confidence these benign lesions that require no intervention. Online supplemental material is available for this article. ^©RSNA, 2022.

Stereotactic radiofrequency ablation as a valid first-line treatment option for hepatocellular adenomas

OBJECTIVES

This study aimed to assess the safety and efficacy of stereotactic radiofrequency ablation (SRFA) in patients with hepatocellular adenomas (HCA).

METHODS

Retrospective analyses of all patients referred for SRFA treatment at our institution between January 2010 and October 2020 revealed 14 patients (10 women; mean age 34.4 [range, 17-73 years]) with 38 HCAs treated through 18 ablation sessions. Ablations were considered successful if a safety margin >5 mm was achieved. Demographic, interventional, and outcome data were collected and analyzed. Primary and secondary technical efficacy rates were assessed based on follow-up images consisting of contrast-enhanced CT or MR scans.

RESULTS

The mean tumor size was 22 mm (range, 7-75 mm). Overall, 37/38 (97.4%) tumors were successfully ablated at the initial SRFA (primary efficacy rate of 97.4%). The median follow-up duration was 49.6 months. No deaths or adenoma-related complications (hemorrhage or malignant transformation) were observed. Disease-free survival rates at 1, 3, and 5 years from the date of the first SRFA were 100%, 85.8%, and 85.8%, respectively. Two patients developed new distant tumors retreated with consecutive re-ablation. No major complications occurred during any of the 18 ablation sessions.

CONCLUSIONS

Percutaneous thermal ablation is efficient in the treatment of HCAs and may thus be considered a valid first-line treatment option. In addition, SRFA allows for an effective, minimally invasive treatment of large and multiple hepatic tumors within one session.

High childhood serum triglyceride concentrations associate with hepatocellular adenoma development in patients with glycogen storage disease type Ia

Background & Aims

Glycogen storage disease type Ia (GSDIa) is an inborn error of carbohydrate metabolism caused by pathogenic variants in the glucose-6-phosphatase catalytic subunit 1 (G6PC1) gene and is associated with hepatocellular adenoma (HCA) formation. Data on risk factors for HCA occurrence in GSDIa are scarce. We investigated HCA development in relation to sex, G6PC1 genotype, and serum triglyceride concentration (TG).

Methods

An observational study of patients with genetically confirmed GSDIa ≥12 years was performed. Patients were categorised for sex; presence of 2, 1, or 0 predicted severe G6PC1 variant (PSV); and median TG during childhood (<12 years; stratified for above/below 5.65 mmol/L, i.e. 500 mg/dl).

Results

Fifty-three patients (23 females) were included, of which 26 patients developed HCA at a median (IQR) age of 21 (17–25) years. At the age of 25 years, 48% of females and 30% of males had developed HCA (log-rank p = 0.045). Two-thirds of patients with GSDIa carried 2 PSVs, 20% carried 1, and 13% carried none. Neither the number of PSVs nor any specific G6PC1 variants were associated with HCA occurrence. Childhood TG was 3.4 (3.0–4.2) mmol/L in males vs. 5.6 (4.0–7.9) mmol/L in females (p = 0.026). Childhood TG >5.65 mmol/L was associated with HCA development at younger age, compared with patients with childhood TG <5.65 mmol/L (18 vs. 33 years; log-rank p = 0.001). Cox regression analysis including TG, sex, and TG–sex interaction correction revealed childhood TG >5.65 mmol/L as an independent risk factor for HCA development (hazard ratio [HR] 6.0; 95% CI 1.2–29.8; p = 0.028).

Conclusions

In patients with GSDIa, high childhood TG was associated with an increased risk of HCA, and earlier onset of HCA development, independent of sex-associated hypertriglyceridaemia, and G6PC1 genotype.

Lay summary

Glycogen storage disease type Ia (GSDIa) is a rare, inherited metabolic disease that can be complicated by liver tumours (hepatocellular adenomas), which in turn may cause bleeding or progress to liver cancer. Risk factors associated with hepatocellular adenoma formation in patients with GSDIa are largely unknown. In our study, we found that high serum triglyceride concentrations during childhood, but not specific genetic variants, were associated with increased risk of hepatocellular adenoma diagnosis later in life.

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Glycogen storage disease Ia (GSDIa) is a metabolic disease caused by mutations in glucose-6-phosphatase catalytic subunit 1 (G6PC1).

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Patients with GSDIa often develop hepatocellular adenoma (HCA), with unclear risk factors.

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Metabolic control in GSDIa is commonly evaluated through serum triglyceride concentration (TG).

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Patients with GSDIa with high childhood TG had increased risk and earlier onset of HCA.

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Sex-associated hypertriglyceridaemia and G6PC1 genotype were not associated with HCA.

Differentiation of hepatocellular adenoma by subtype and hepatocellular carcinoma in non-cirrhotic liver by fractal analysis of perfusion MRI

Background

To investigate whether fractal analysis of perfusion differentiates hepatocellular adenoma (HCA) subtypes and hepatocellular carcinoma (HCC) in non-cirrhotic liver by quantifying perfusion chaos using four-dimensional dynamic contrast-enhanced magnetic resonance imaging (4D-DCE-MRI).

Results

A retrospective population of 63 patients (47 female) with histopathologically characterized HCA and HCC in non-cirrhotic livers was investigated. Our population consisted of 13 hepatocyte nuclear factor (HNF)-1α-inactivated (H-HCAs), 7 β-catenin-exon-3-mutated (b^ex3-HCAs), 27 inflammatory HCAs (I-HCAs), and 16 HCCs. Four-dimensional fractal analysis was applied to arterial, portal venous, and delayed phases of 4D-DCE-MRI and was performed in lesions as well as remote liver tissue. Diagnostic accuracy of fractal analysis was compared to qualitative MRI features alone and their combination using multi-class diagnostic accuracy testing including kappa-statistics and area under the receiver operating characteristic curve (AUC). Fractal analysis allowed quantification of perfusion chaos, which was significantly different between lesion subtypes (multi-class AUC = 0.90, p < 0.001), except between I-HCA and HCC. Qualitative MRI features alone did not allow reliable differentiation between HCA subtypes and HCC (κ = 0.35). However, combining qualitative MRI features and fractal analysis reliably predicted the histopathological diagnosis (κ = 0.89) and improved differentiation of high-risk lesions (i.e., HCCs, b^ex3-HCAs) and low-risk lesions (H-HCAs, I-HCAs) from sensitivity and specificity of 43% (95% confidence interval [CI] 23–66%) and 47% (CI 32–64%) for qualitative MRI features to 96% (CI 78–100%) and 68% (CI 51–81%), respectively, when adding fractal analysis.

Conclusions

Combining qualitative MRI features with fractal analysis allows identification of HCA subtypes and HCCs in patients with non-cirrhotic livers and improves differentiation of lesions with high and low risk for malignant transformation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-022-01223-6.

Subtyping of hepatocellular adenoma: a machine learning-based approach

Subtyping of hepatocellular adenoma (HCA) is an important task in practice as different subtypes may have different clinical outcomes and management algorithms. Definitive subtyping is currently dependent on immunohistochemical and molecular testing. The association between some morphologic/clinical features and HCA subtypes has been reported; however, the predictive performance of these features has been controversial. In this study, we attempted machine learning based methods to select an efficient and parsimonious set of morphologic/clinical features for differentiating a HCA subtype from the others, and then assessed the performance of the selected features in identifying the correct subtypes. We first examined 50 liver HCA resection specimens collected at the University of Washington and Kobe University/Kings College London, including HNF1α-mutated HCA (H-HCA) (n = 16), inflammatory HCA (I-HCA) (n = 20), beta-catenin activated HCA (β-HCA) (n = 8), and unclassified HCA (U-HCA) (n = 6). Twenty-six morphologic/clinical features were assessed. We used LASSO (least absolute shrinkage and selection operator) to select key features that could differentiate a subtype from the others. We further performed SVM (support vector machine) analysis to assess the performance (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy) of the selected features in HCA subtyping in an independent cohort of liver resection samples (n = 20) collected at the University of Wisconsin-Madison. With some overlap, different combinations of morphologic/clinical features were selected for each subtype. Based on SVM analysis, the selected features classified HCA into correct subtypes with an overall accuracy of at least 80%. Our findings are useful for initial diagnosis and subtyping of HCA, especially in clinical settings without access to immunohistochemical and molecular assays.

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.

Preneoplastic lesions in the liver: Molecular insights and relevance for clinical practice

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the most frequent primary liver cancers, accounting for approximately 80% and 15%, respectively. HCC carcinogenesis occurs mostly in cirrhosis and is a complex multi-step process, from precancerous lesions (low-grade and high-grade dysplastic nodules) to progressed HCC. During the different stages of liver carcinogenesis, there is an accumulation of pathological, genetic and epigenetic changes leading to initiation, malignant transformation and finally tumour progression. In contrast, a small subset of HCC occurs in normal liver from the transformation of hepatocellular adenoma (HCA), a benign hepatocellular tumour. The recent molecular classification enables to stratify HCAs according to their risk of complication, in particular malignant transformation, associated with mutations in exon 3 of the catenin beta 1 (CTNNB1) gene. Cholangiocarcinoma (CCA) derives from the multistep malignant transformation of preneoplastic lesions, like biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB), for which a pre-operative diagnosis remains difficult. Different genetic alterations are involved in BilIN and IPNB progression, leading to the development of tubular or intestinal adenocarcinoma. The aims of this review are to describe the main clinical and molecular features of preneoplastic lesions leading to the development of HCC and CCA, their implications in clinical practice and the perspectives for future research.

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.

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.

Non-invasive diagnosis and follow-up of benign liver tumours

Hepatocellular benign liver tumours are mainly developed on normal liver and include hepatic hemangioma, focal nodular hyperplasia and hepatocellular adenoma from the most frequent to the less frequent. The diagnosis of hepatic hemangioma and of simple hepatic biliary cysts can be performed using non-invasive criteria using liver ultrasonography or contrast enhanced MRI. Most of the time the diagnosis of focal nodular hyperplasia can be achieved using contrast-enhanced ultrasonography or contrast enhanced MRI with an additional value of hepatobiliary contrast-agent in this setting. Rarely, if a doubt persists, a tumour and non-tumour liver biopsy can be required in order to establish the diagnosis. As hepatic hemangioma, simple hepatic biliary cysts and focal nodular hyperplasia are not associated with complications, they don't require any treatments or follow-up. Hepatocellular adenomas are mainly diagnosed at histology on surgical samples or liver biopsy even if some radiological features are highly suggestive of several subtypes of hepatocellular adenomas. Finally, the management of hepatocellular adenomas should be guided according to the tumour size, gender but also to the molecular subtypes.

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.

Safety and clinical activity of intratumoral MEDI9197 alone and in combination with durvalumab and/or palliative radiation therapy in patients with advanced solid tumors

Background

MEDI9197 is an intratumorally administered toll-like receptor 7 and 8 agonist. In mice, MEDI9197 modulated antitumor immune responses, inhibited tumor growth and increased survival. This first-time-in-human, phase 1 study evaluated MEDI9197 with or without the programmed cell death ligand-1 (PD-L1) inhibitor durvalumab and/or palliative radiation therapy (RT) for advanced solid tumors.

Patients and methods

Eligible patients had at least one cutaneous, subcutaneous, or deep-seated lesion suitable for intratumoral (IT) injection. Dose escalation used a standard 3+3 design. Patients received IT MEDI9197 0.005–0.055 mg with or without RT (part 1), or IT MEDI9197 0.005 or 0.012 mg plus durvalumab 1500 mg intravenous with or without RT (part 3), in 4-week cycles. Primary endpoints were safety and tolerability. Secondary endpoints included pharmacokinetics, pharmacodynamics, and objective response based on Response Evaluation Criteria for Solid Tumors version 1.1. Exploratory endpoints included tumor and peripheral biomarkers that correlate with biological activity or predict response.

Results

From November 2015 to March 2018, part 1 enrolled 35 patients and part 3 enrolled 17 patients; five in part 1 and 2 in part 3 received RT. The maximum tolerated dose of MEDI9197 monotherapy was 0.037 mg, with dose-limiting toxicity (DLT) of cytokine release syndrome in two patients (one grade 3, one grade 4) and 0.012 mg in combination with durvalumab 1500 mg with DLT of MEDI9197-related hemorrhagic shock in one patient (grade 5) following liver metastasis rupture after two cycles of MEDI9197. Across parts 1 and 3, the most frequent MEDI9197-related adverse events (AEs) of any grade were fever (56%), fatigue (31%), and nausea (21%). The most frequent MEDI9197-related grade ≥3 events were decreased lymphocytes (15%), neutrophils (10%), and white cell counts (10%). MEDI9197 increased tumoral CD8+ and PD-L1+ cells, inducing type 1 and 2 interferons and Th1 response. There were no objective clinical responses; 10 patients in part 1 and 3 patients in part 3 had stable disease ≥8 weeks.

Conclusion

IT MEDI9197 was feasible for subcutaneous/cutaneous lesions but AEs precluded its use in deep-seated lesions. Although no patients responded, MEDI9197 induced systemic and intratumoral immune activation, indicating potential value in combination regimens in other patient populations.

Trial registration number

NCT02556463.

Liver transplantation for benign liver tumors

Benign liver tumors are common lesions that are usually asymptomatic and are often found incidentally due to recent advances in imaging techniques and their widespread use. Although most of these tumors can be managed conservatively or treated by surgical resection, liver transplantation (LT) is the only treatment option in selected patients. LT is usually indicated in patients that present with life-threatening complications, when the lesions are diffuse in the hepatic parenchyma or when malignant transformation cannot be ruled out. However, due to the significant postoperative morbidity of the procedure, scarcity of available donor liver grafts, and the benign course of the disease, the indications for LT are still not standardized. Hepatic adenoma and adenomatosis, hepatic hemangioma, and hepatic epithelioid hemangioendothelioma are among the most common benign liver tumors treated by LT. This article reviews the role of LT in patients with benign liver tumors. The indications for LT and long-term outcomes of LT are presented.

Focal hepatic intrinsically hyperattenuating lesions at unenhanced CT: Not always calcifications

Due to the growing use of CT, there has been an increase in the frequency of detecting focal liver lesions. Intrinsically hyperattenuating hepatic lesions or pseudolesions are not uncommon at unenhanced CT. Hyperattenuating hepatic lesions can be divided into non-calcified and calcified. Causes of intrinsic hyperattenuation include hemorrhage, thrombosis, and calcifications. Focal liver lesions can show hyperattenuation on unenhanced CT in case of severe liver steatosis. Recognition of etiologies associated with hyperattenuation on unenhanced CT can help the radiologist in characterizing focal liver lesions and pseudolesions. In this paper, we describe the spectrum of intrinsically hyperattenuating focal liver lesions and pseudolesions at unenhanced CT.

Proteomic Profiling of Hepatocellular Adenomas Paves the Way to Diagnostic and Prognostic Approaches

BACKGROUND AND AIMS

Through an exploratory proteomic approach based on typical hepatocellular adenomas (HCAs), we previously identified a diagnostic biomarker for a distinctive subtype of HCA with high risk of bleeding, already validated on a multicenter cohort. We hypothesized that the whole protein expression deregulation profile could deliver much more informative data for tumor characterization. Therefore, we pursued our analysis with the characterization of HCA proteomic profiles, evaluating their correspondence with the established genotype/phenotype classification and assessing whether they could provide added diagnosis and prognosis values.

APPROACH AND RESULTS

From a collection of 260 cases, we selected 52 typical cases of all different subgroups on which we built a reference HCA proteomics database. Combining laser microdissection and mass-spectrometry-based proteomic analysis, we compared the relative protein abundances between tumoral (T) and nontumoral (NT) liver tissues from each patient and we defined a specific proteomic profile of each of the HCA subgroups. Next, we built a matching algorithm comparing the proteomic profile extracted from a patient with our reference HCA database. Proteomic profiles allowed HCA classification and made diagnosis possible, even for complex cases with immunohistological or genomic analysis that did not lead to a formal conclusion. Despite a well-established pathomolecular classification, clinical practices have not substantially changed and the HCA management link to the assessment of the malignant transformation risk remains delicate for many surgeons. That is why we also identified and validated a proteomic profile that would directly evaluate malignant transformation risk regardless of HCA subtype.

CONCLUSIONS

This work proposes a proteomic-based machine learning tool, operational on fixed biopsies, that can improve diagnosis and prognosis and therefore patient management for HCAs.

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.

Surgical outcomes of laparoscopic and open resection of benign liver tumours in the Netherlands: a nationwide analysis

BACKGROUND

Data on surgical outcomes of laparoscopic liver resection (LLR) versus open liver resection (OLR) of benign liver tumour (BLT) are scarce. This study aimed to provide a nationwide overview of postoperative outcomes after LLR and OLR of BLT.

METHODS

This was a nationwide retrospective study including all patients who underwent liver resection for hepatocellular adenoma, haemangioma and focal nodular hyperplasia in the Netherlands from 2014 to 2019. Propensity score matching (PSM) was applied to compare 30-day overall and major morbidity and 30-day mortality after OLR and LLR.

RESULTS

In total, 415 patients underwent BLT resection of whom 230 (55.4%) underwent LLR. PSM for OLR and LLR resulted in 250 matched patients. Median (IQR) length of stay was shorter after LLR than OLR (4 versus 6 days, 5.0-8.0, p < 0.001). Postoperative 30-day overall morbidity was lower after LLR than OLR (12.0% vs. 22.4%, p = 0.043). LLR was associated with reduced 30-day overall morbidity in multivariable analysis (aOR:0.46, CI:0.22-0.95, p = 0.043). Both 30-day major morbidity and 30-day mortality were not different.

CONCLUSIONS

LLR for BLT is associated with shorter hospital stay and reduced overall morbidity and is preferred if technically feasible.

Hepatocellular Adenoma Risk Factors of Hemorrhage: Size is not the only Concern! Single Center Retrospective Experience of 261 Patients

OBJECTIVE

Our aim was to determine independent risk factors of clinical bleeding of hepatocellular adenoma (HCA) in order to define a better management strategy.

SUMMARY BACKGROUND DATA

HCA is a rare benign liver tumor with severe complications: malignant transformation which is rare (5-8%) and more often, hemorrhage (20-27%). To date, only size > 5 cm and histological subtype (possibly sonic hedgehog) are associated with bleeding, but these criteria are not clearly established.

METHODS

We retrospectively collected data from a cohort of 268 patients with HCA managed in our tertiary center, from 1984 to 2020 and focused on clinical bleeding. Hemorrhage was considered as severe when it required intensive care and moderate when bleeding symptoms required a hospitalization. We included 261 patients, of which 130 (49.8%) had multiple HCAs or liver adenomatosis. All surgical specimen and liver biopsy were reviewed by an experienced liver pathologist and reclassified in the light of the current immunohistochemistry. Mean duration of follow-up was 93.3 months (range 1-363). We analyzed type, frequency, consequences of bleeding and risk factors among clinical data and HCA characteristics.

RESULTS

Eighty-three HCA (31.8%) were hemorrhagic. There were 4 pregnant women with one newborn death. One patient died before treatment. Surgery was performed in 78 (94.0%) patients. Mortality was nil and severe complications occurred in 11.5%. Multivariate analysis identified size (OR 1.02 [1.01-1.02], p < 0.001), shHCA (OR 21.02 [5.05-87.52], p < 0.001), b-catenin mutation on exon 7/8 (OR 6.47 [1.78-23.55], p = 0.0046), chronic alcohol consumption (OR 9.16 [2.47-34.01], p < 0.001) as independent risk factors of clinical bleeding.

CONCLUSIONS

This series, focused on the hemorrhagic risk of HCA, shows that size, but rather more molecular subtype is determinant in the natural history of HCA.

Stereotactic radiofrequency ablation of a variety of liver masses in children

BACKGROUND AND AIMS

Surgical resection is currently the cornerstone of liver tumor treatment in children. In adults radiofrequency ablation (RFA) is an established minimally invasive treatment option for small focal liver tumors. Multiprobe stereotactic RFA (SRFA) with intraoperative image fusion to confirm ablation margins allows treatment for large lesions. We describe our experience with SRFA in children with liver masses.

METHODS

SRFA was performed in 10 patients with a median age of 14 years (range 0.5-17.0 years) suffering from liver adenoma (n = 3), hepatocellular carcinoma (n = 1), hepatoblastoma (n = 2), myofibroblastic tumor (n = 1), hepatic metastases of extrahepatic tumors (n = 2) and infiltrative hepatic cysts associated with alveolar echinococcosis (n = 1). Overall, 15 lesions with a mean lesion size of 2.6 cm (range 0.7-9.5 cm) were treated in 11 sessions.

RESULTS

The technical success rate was 100%, as was the survival rate. No transient adverse effects higher than grade II (Clavien and Dindo) were encountered after interventions. The median hospital stay was 5 d (range 2-33 d). In two patients who subsequently underwent transplant hepatectomy complete ablation was histologically confirmed. Follow-up imaging studies (median 55 months, range 18-129 months) revealed no local or distant recurrence of disease in any patient.

CONCLUSIONS

SRFA is an effective minimal-invasive treatment option in pediatric patients with liver tumors of different etiologies.

From an Incidental Finding to an Emergent Treatment: A Case Report of a Hepatic Adenomatosis and Large Ruptured Hepatic Adenoma

Introduction. Hepatic adenoma is an uncommon benign liver tumor presenting as solitary lesions or even rarely as hepatic adenomatosis. Large lesions carry a risk of rupture, hemorrhage, and malignant transformation. This case report aims to increase awareness about risk factors for hepatic adenomas, considering the increasing prevalence of obesity and the widespread use of oral contraceptive pills. Case Presentation. A 20-year-old obese female who was taking oral contraceptive pills for seven years presented to the emergency department with vomiting and abdominal pain caused by gastroenteritis. On imaging, multiple hepatic adenomas, including two lesions 6 and 9 cm in diameter, were incidentally found. During the hospitalization, the patient suddenly developed acute anemia and rupture of the largest lesion, which was promptly treated with arterial embolization. Discussion. Obesity and exposure to hormones are well-known risk factors for hepatic adenomas. The incidence of hepatic adenomas is steadily increasing because of the prevalence of obesity, especially among females. Lifestyle interventions for weight loss and discontinuation of oral contraceptive pills are considered a conservative treatment of hepatic adenomas. Large lesions possess the risk of malignant transformation and rupture and require surgical excision.

Guidelines for the Treatment of Hepatocellular Adenoma in the Era of Molecular Biology: An Experience-Based Surgeons' Perspective

BACKGROUND

Hepatocellular adenoma (HA) is a rare benign liver tumor with increasing incidence affecting young women. In the last years, much has changed in diagnosis, classification, and treatment, due to the identification of different molecular subtypes. With the evolving knowledge, especially on molecular characteristics of the disease, we are far from a consensus of how to deal with such a multifaceted benign disease METHODS: In the last 20 years, we have treated 134 patients with HA with a mean age of 28 years, being 126 women. Fifty patients had a history of abdominal pain and 13 patients had an acute episode of pain due to rupture and bleeding. Until 2009, adenomas larger than 4 cm in diameter were resected, regardless of gender. From 2010 to 2016, only adenomas larger than 5 cm were referred for surgical treatment. Since 2016, resection was indicated in all female patients with non-steatotic adenomas larger than 5 cm and all adenomas in men.

RESULTS AND DISCUSSION

One hundred twenty-four patients were submitted to resection, being in 21 major resections. Since 2010, 74% of resections were done laparoscopically. Patients with ruptured adenomas were treated with transarterial embolization. Morbidity rate was 8.1% with no mortality. Authors discuss point-by-point all the aspects and presentations of the disease and the best approach. We proposed a therapeutic guideline based on the best available evidence and in our experience.

CONCLUSIONS

Due to the complexity of the disease, the treatment of HA is one the best examples of an individualized approach.

18F-FDG PET/CT of hepatocellular adenoma subtypes and review of literature

INTRODUCTION

This study evaluates 18F-FDG PET/CT imaging characteristics of pathologically proven hepatocellular adenoma (HCA) subtypes.

METHODS

This is a retrospective review of an institutional database (2011-2017) for subjects with a pathologic diagnosis of hepatic adenomas established within 6 months of a pre-treatment 18F-FDG PET/CT exam. An expert pathological review by a hepatopathologist was performed to confirm diagnosis and subtype HCA. A review of the 18F-FDG PET/CT exams was performed by two board-certified nuclear radiologists in consensus. Corresponding demographic and clinical data were obtained by electronic chart review.

RESULTS

Nine subjects were identified. An HCA subtype was established in seven subjects (4 HNF1A-mutated and 3 Inflammatory). The mean HCA lesion size was 2.8 cm (range 0.6-6.2, SD 2.0) with a mean SUVmax of 5.9 (range 2.1-18.9, SD 5.1). The SUV values of HNF1A-mutated HCA were significantly higher than inflammatory HCA: lesion SUVmax (5.3 ± 1.48 vs. 2.8 ± 0.59, p < 0.033), lesion-to-liver SUVmax ratio (1.4 ± 0.22 vs. 0.8 ± 0.21, p = 0.031), lesion SUVmean (3.6 ± 0.37 vs. 2.0 ± 0.46, p = 0.0086).

CONCLUSION

HNF1A-mutated HCA may have greater SUV values than inflammatory HCA on 18F-FDG PET/CT exams. However, there are contradictory data in the literature and further investigation is warranted.

A case study of glycogen storage disease type Ia presenting with multiple hepatocellular adenomas: an analysis by gadolinium ethoxybenzyl-diethylenetriamine-pentaacetic acid magnetic resonance imaging

Glycogen storage disease type Ia (GSD Ia) is a rare disease caused by a deficiency of hepatic glucose-6-phosphatase (G6Pase). Here, we report a 17-year-old Chinese boy with GSD Ia. Clinical manifestations of the patient included hepatomegaly, growth retardation, doll face, and biochemical abnormalities, including hypoglycaemia, hyperuricaemia, and hyperlipidaemia. The computed tomography (CT) and gadolinium ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) magnetic resonance imaging (MRI) revealed multiple masses in the left and right hemiliver. These masses presented as different dynamic enhanced patterns in the Gd-EOB-DTPA MRI. In addition, a large amount of glycogen deposit was detected in the liver tissue biopsy. Liver puncture confirmed that the masses were hepatocellular adenomas (HCAs). Genetic analyses confirmed the presence of liver metabolic disease, and the final clinical diagnostic was GSD Ia. The patient's clinical manifestations were significantly improved following regular treatment with raw corn starch for 9 months. Unfortunately, it was suspected that parts of the adenoma had undergone malignant transformation.

A Multicenter, 10-Year Experience With Hepatocellular Adenoma: Risk Factors and Disease Course

BACKGROUND

Management of hepatocellular adenoma (HA) is marked by a paucity of recent studies. Long-term follow-up data from an equal access health care system may facilitate our understanding of the natural disease course of HA and identify modifiable risk factors.

METHODS

A multi-institutional, retrospective review of patients with HA from 2008-2017 was performed. Patient demographics, disease characteristics, and clinical outcomes were analyzed.

RESULTS

Of 124 patients identified, 94% were women with a mean age at diagnosis of 39.5 years (range 20-82). Median follow-up was 22.5 months (range 0-114) with thirty-four (27.4%) patients eventually undergoing hepatectomy. Mean BMI of the study population was 30.5 kg/m² (range 16-72). Stratified by size, average BMI for adenomas ≥5 cm was 34 kg/m² compared to 28 kg/m² for those <5 cm (P < .05). The predominant symptom at presentation was abdominal pain (41.1%), while just 4% presented with acute rupture. Overall incidence of the malignancy was 2.5%. Among all patients, oral contraceptive use was documented in 74 (59.7%) patients, of whom 36 (29.0%) discontinued OC for at least six months. Regression after OC cessation occurred in seven patients (19.4%) while the majority (77.8%) remained stable.

DISCUSSION

This decade-long review analyzing the impact of modifiable risk factors identifies a direct correlation between BMI and hepatocellular adenoma size. Rupture and malignant transformation are rare entities. Cessation of OC appears to be an effective strategy in the management of hepatic adenoma. Further investigations are warranted to determine if addressing modifiable risk factors such as BMI might induce further HA regression.

Hepatocellular adenomas: review of pathological and molecular features

Hepatocellular adenoma (HCA) is a rare benign liver neoplasm which predominantly occurs in women in the reproductive age group taking oral contraception. Since 2002, the terminology HCA has defined an heterogeneous group of neoplastic benign hepatocellular proliferations composed of different subtypes. The genotype-phenotype classification led to the description of 5 well-recognized subtypes based on morphological and immunophenotypical features, that are currently used in practice: HNF1A inactivated HCA, inflammatory HCA, β-catenin mutated HCA, sonic hedgehog HCA, and unclassified HCA. The main complications observed in HCAs are bleeding and malignant transformation. Risk of malignant transformation into hepatocellular carcinoma (HCC), more frequent in men, is also dependent to tumor size and HCA subtype, reaching 40% in β-catenin mutated HCA. The distinction of HCA from well-differentiated HCC remains difficult in some cases, leading to the diagnosis of so-called "atypical/borderline HCA". The management of HCA is now based on multidisciplinary approach including clinicians, radiologists, and pathologists integrating gender, tumor size, and HCA subtyping.

Interventional radiological management of hepatobiliary disorders in pregnancy

Hepatobiliary disorders are common in pregnancy and pose a management challenge. Minimally invasive interventional radiological (IR) techniques allow safe and effective management of these disorders. However, the available literature is scarce. Radiological interventions in this group of patients mandate a clear understanding of the risks of radiation to the fetus. The IR physician involved in the care of these patients should be aware of the measures to minimize the exposure to ionizing radiation. Additionally, the risk-benefit ratio should be clearly defined in a multidisciplinary discussion involving IR physicians, obstetricians, and gastroenterologists. This review is an effort to address issues related to the application of IR procedures for hepatobiliary disorders in pregnant patients.

Spontaneous hepatic haemorrhage secondary to ruptured hepatocellular adenoma in a young male patient

A 27-year-old man presented with acute right upper quadrant abdominal pain and vomiting. He was clinically in hypovolaemic shock. Investigations revealed normocytic anaemia with a normal bilirubin and moderate liver function test abnormalities. CT abdomen and pelvis demonstrated haemoperitoneum and a large solitary hepatic mass in segments V and VI, suspicious for a ruptured hepatic tumour. Massive transfusion protocol was commenced and angioembolisation of the inferior branch of the right hepatic artery was undertaken. Despite this, his haemorrhagic shock was resistant to resuscitation. Thus, he underwent emergent exploratory laparotomy, which resulted in segments V and VI liver resection and packing. Re-look laparotomy 2 days following initial exploration was performed where haemostasis was confirmed. Histopathology revealed a ruptured well-differentiated hepatocellular adenoma. The patient made a good recovery following a 2-week admission.

Benign Liver Tumors

Background

Due to the frequent use of medical imaging including ultrasonography, the incidence of benign liver tumors has increased. There is a large variety of different solid benign liver tumors, of which hemangioma, focal nodular hyperplasia (FNH), and hepatocellular adenoma (HCA) are the most frequent. Advanced imaging techniques allow precise diagnosis in most of the patients, which reduces the need for biopsies only to limited cases. Patients with benign liver tumors are mostly asymptomatic and do not need any kind of treatment. Symptoms can be abdominal pain and pressure effects on adjacent structures. The 2 most serious complications are bleeding and malignant transformation.

Summary

This review focuses on hepatic hemangioma (HH), FNH, and HCA, and provides an overview on clinical presentations, surgical and interventional treatment, as well as conservative management. Treatment options for HHs, if indicated, include liver resection, radiofrequency ablation, and transarterial catheter embolization, and should be carefully weighed against possible complications. FNH is the most frequent benign liver tumor without any risk of malignant transformation, and treatment should only be restricted to symptomatic patients. HCA is associated with the use of oral contraceptives or other steroid medications. Unlike other benign liver tumors, HCA may be complicated by malignant transformation. HCAs have been divided into 6 subtypes based on molecular and pathological features with different risk of complication.

Key Message

The vast majority of benign liver tumors remain asymptomatic, do not increase in size, and rarely need treatment. Biopsies are usually not needed as accurate diagnosis can be obtained using modern imaging techniques.

A systematic review on the complications and management of hepatic adenomas: a call for a new approach

Hepatic adenomas are benign hepatic lesions with heterogeneous characteristics. Awareness of complications, including haemorrhage and malignant transformation, has improved alongside a concurrent rise in their detection. Monitoring and management guidelines, however, remain inconsistent. This systematic review analyses the natural history of hepatic adenomas, and existing and novel risk factors associated with haemorrhage and malignant transformation. Results of this systematic review commonly identified male sex, and the beta-catenin histopathological hepatic adenoma subtype, as risk factors for malignant transformation, whilst those associated with haemorrhage included lesion size and number, exophytic nature, and recent hormone use. Overall, females demonstrated higher rates of haemorrhage, whilst males exhibited a higher risk of hepatocellular carcinoma development. This systematic review highlights that tumour size and subtype may not be as characteristically linked with complications as previously thought. We have additionally reported novel risk factors contributing to development of hepatic adenoma-related complications. We conclude by highlighting the risk of taking a conservative approach to seemingly low-risk lesions and suggest revised practice guidelines.

Management of benign liver tumors

Benign liver tumors in children are far less frequent than their malignant counterparts. Recently, there have been advances of diagnostic procedures and novel treatments with improved classification as a result. While malignant pediatric liver tumors have been comprehensively addressed by multicenter international tumor trials, benign tumors have more usually relied upon individualised workup and treatment. Due to the rarity and heterogeneity of these different entities, large studies are lacking. In this article the authors highlight the spectrum of benign liver tumors with special focus on specific clinical features, pathology, and treatment.

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.

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 β-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 β-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.

Hepatocellular adenoma in the paediatric population: Molecular classification and clinical associations

Hepatocellular adenomas (HCAs) represent rare, benign liver tumours occurring predominantly in females taking oral contraceptives. In children, HCAs comprise less than 5% of hepatic tumours and demonstrate association with various conditions. The contemporary classification of HCAs, based on their distinctive genotypes and clinical phenotypes, includes hepatocyte nuclear factor 1 homeobox alpha-inactivated HCAs, beta-catenin-mutated HCAs, inflammatory HCAs, combined beta-catenin-mutated and inflammatory HCAs, sonic hedgehog-activated HCAs, and unclassified HCAs. In children, there is a lack of literature on the characteristics and distribution of HCA subtypes. In this review, we summarized different HCA subtypes and the clinicopathologic spectrum of HCAs in the paediatric population.

Hepatic adenoma rupture following portal vein embolization

Hepatic adenomas are benign liver tumors typically found in females of reproductive age. Though benign, hepatic adenomas are highly vascularized tumors, thus rupture and consequent hemorrhage present a feared complication. We report a case of a 31-year-old woman with hepatic adenoma who underwent preoperative portal vein embolization and subsequently suffered a rupture of her tumor. We postulate that the change in blood flow after portal vein embolization, a phenomenon known as the hepatic artery buffer response, may have contributed to the tumor rupture, though the possibility that the rupture was purely incidental remains. There is currently no prior report of such rupture occurring following portal vein embolization, and this case brings to light a potentially fatal complication of a generally safely regarded procedure in patients with hepatic adenoma.

Current concepts in ablative procedures for primary benign liver lesions: a step forward to minimize the invasiveness of treatment when deemed necessary

With increased use of medical imaging, the incidental detection of benign solid liver tumors has become more frequent. Facing with benign disease, the indications for surgery are still object of discussion in light of the stable natural course of most lesions and obvious drawbacks of any surgical intervention; therefore, in most situations, a conservative approach is recommended, and surgery is mainly reserved for those cases with persistent or worsening symptoms, or who are at risk for complications as malignant transformation. The advent of ablative techniques has widened the range of treatment options available to these patients, presenting as a valid alternative to resection in terms of safety and efficacy in selected cases, particularly in patients who are considered poor surgical candidates and with smaller lesions. This review outlines the role of percutaneous ablative methods for benign solid liver tumors that are encountered in adults, providing a per histology analysis of the existing evidence. The up-to-date strategies for management of the most common benign solid tumors are recapitulated.

Long-term Evolution of Hepatocellular Adenomas at MRI Follow-up

Background Hepatocellular adenomas (HCAs) are rare benign liver tumors. Guidelines recommend continued surveillance of patients diagnosed with HCAs, but these guidelines are mainly based on small studies or expert opinion. Purpose To analyze the long-term evolution of HCAs, including solitary and multiple lesions, and to identify predictive features of progression with MRI. Materials and Methods In a retrospective study, patients diagnosed with pathologically proven solitary or multiple HCAs between January 2004 and December 2015 were included; β-catenin-mutated HCAs and HCAs with foci of malignancy were considered to be at risk for progression. MRI examinations were analyzed, and tumor evolution was evaluated by using Response Evaluation Criteria in Solid Tumors, version 1.1. Student t, Mann-Whitney, χ², Fisher exact, and McNemar tests were used, as appropriate. Results In total, 118 patients (mean age, 40 years ± 10 [standard deviation]; 108 women) were evaluated, including 41 with a solitary HCA (mean age, 40 years ± 14; 36 women) and 77 with multiple HCAs (mean age, 40 years ± 10; 72 women). At a median follow-up of 5 years, 37 of 41 (90%) patients with a solitary HCA and 55 of 77 (71%) patients with multiple HCAs showed stable or regressive disease. After resection of solitary HCAs, new lesions appeared in only two of 29 (7%) patients, both of whom had HCAs at risk of progression. In patients with multiple HCAs, hepatocyte nuclear factor 1α-inactivated HCAs showed a higher rate of progression compared with inflammatory HCAs (11 of 26 [42%] vs seven of 37 [19%], P = .04) despite lower use (28 of 32 patients [88%] vs 45 of 45 patients [100%]; P = .03) and shorter duration (mean, 12.0 years ± 7.5 vs 19.2 years ± 9.2; P = .001) of oral contraceptive intake. Conclusion Long-term MRI follow-up showed that 78% of hepatocellular adenomas had long-term stability or regression. After resection of solitary hepatocellular adenomas, new lesions occurred only in hepatocellular adenomas at risk of progression. Patients with multiple hepatocellular adenomas were more likely to show progressive disease, with hepatic nuclear factor 1α-inactivated hepatocellular adenomas being the most common subtype showing progression. © RSNA, 2020 Online supplemental material is available for this article.