Pathological Diagnosis of Hepatocellular Cellular Adenoma according to the Clinical Context

Integrated genotype-phenotype analysis of familial adenomatous polyposis-associated hepatocellular adenomas

Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome caused by a germline mutation in the adenomatous polyposis coli (APC) gene, characterized by numerous colorectal adenomas. In addition, FAP patients may develop extraintestinal manifestations. Several cases of hepatocellular adenomas (HCA) detected accidentally in FAP patients have raised the so-far unsolved question of whether they represent a specific manifestation of FAP or a mere coincidence. To investigate the incidence of liver tumors in FAP patients, we analyzed our diagnostic database from 1991 to 2021. Among the 58 hepatic mass lesions identified, five HCAs occurring in three patients with FAP were identified, and comprehensive morphological, immunohistological, and molecular analysis employing targeted next-generation sequencing was conducted for characterization. The HCAs in this study showed no cytological or histological atypia. They displayed a diffuse, strong positivity for glutamine synthetase but no nuclear beta-catenin immunostaining. In two patients, the adenomas showed moderate immunoreactivity against serum amyloid A. Consistent with the diagnosis of FAP, molecular profiling revealed a pathogenic germline mutation of the APC gene in all analyzed adenomas as well as deleterious somatic second hits. All somatic mutations were localized between codons 1345 and 1577. No mutations were found in the catenin beta 1 gene. HCA in FAP patients can be a specific, although rare, neoplastic manifestation of this inborn disease and represents a distinct subgroup of HCAs. These benign tumors represent an important differential diagnosis for hepatic metastases in FAP patients and require adequate clinical and molecular (diagnostic) assessments for optimal patient guidance.

Is This Patient's Liver Mass Cancer?

Undiagnosed liver lesions are important findings that can affect the physical and mental well-being of patients. They are usually incidental findings identified while clinicians are performing other imaging tests. It is important for clinicians and patients to identify the causative factors for these lesions in order to further reduce risk, develop treatment plans, and produce better outcomes. Both men and women can develop liver lesions, which may require surgical intervention. Knowing the key risk factors for common lesions can help clinicians confidently diagnose patients without costly workup.

Hepatic Adenoma

Hepatic adenomas are rare, usually benign tumors of the liver with a small risk for bleeding and malignant transformation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND & AIMS

Liver adenomatosis (LA) is characterized by the presence of at least 10 hepatocellular adenomas (HCAs), but the natural history of this rare liver disorder remains unclear. Thus, we aimed to reappraise the natural history and the risk of complications in a cohort of patients with at least 10 HCAs.

METHODS

We analyzed the natural history of 40 patients with LA, excluding glycogen storage disorders, in a monocentric cohort. Pathological examination was performed, with immunostaining and molecular biology carried out on surgical specimens or liver biopsies.

RESULTS

Forty patients (36 female) were included with a median follow-up of 10.6 (1.9-26.1) years. Six (15%) patients had familial LA, all with germline HNF1A mutations. Median age at diagnosis was 39 (9-55) years. Thirty-three (94%) women had a history of oral contraception, and 29 (81%) women had a pregnancy before LA diagnosis. Overall, thirty-seven (93%) patients underwent surgery at diagnosis. Classification of HCAs showed 46% of patients with HNF1A-mutated HCA, 31% with inflammatory HCA, 3% with sonic hedgehog HCA, 8% with unclassified HCA. Only 15% of the patients demonstrated a "mixed LA" with different HCA subtypes. Hepatic complications were identified in 7 patients: 1 patient (3%) died from recurrent hepatocellular carcinoma after liver transplantation; 6 (15%) had hemorrhages, of which 5 occurred at diagnosis, with 1 fatal case during pregnancy, and 2 occurred in male patients with familial LA. Four patients (10%) had repeated liver resections. Finally, 4 (10%) patients developed extrahepatic malignancies during follow-up.

CONCLUSIONS

The diversity in HCA subtypes, as well as the occurrence of bleeding and malignant transformation during long-term follow-up, underline the heterogeneous nature of LA, justifying close and specific management. In patients with germline HNF1A mutation, familial LA occurred equally frequently in males and females, with a higher rate of bleeding in male patients.

LAY SUMMARY

Liver adenomatosis is a rare disease characterized by the presence of 10 or more hepatocellular adenomas that may rarely be of genetic origin. Patients with liver adenomatosis have multiple adenomas of different subtypes, with a risk of bleeding and malignant transformation that justify a specific management and follow-up.

New MRI features improve subtype classification of hepatocellular adenoma

OBJECTIVE

MRI is crucial for the classification of hepatocellular adenomas (HCA) into subtypes. Our objective was to review and increase MRI criteria for subtype classification and define the limits.

METHODS

Pathological and radiological data of 116 HCAs were retrospectively analyzed to investigate MRI features of HCA pathological subtypes. Risk for complication was also evaluated with regard to subtype and tumor size.

RESULTS

38/43 (88%) HNF1α-mutated HCAs (H-HCAs) were discriminated by (i) fatty component (homogeneous or heterogeneous) and (ii) hypovascular pattern, with a sensitivity of 88% and a specificity of 97%. 51/58 (88%) inflammatory HCAs (IHCAs) displayed features of sinusoidal dilatation (SD) including three different patterns (global SD, atoll sign, and a new "crescent sign" corresponding to a partial peripheral rim, hyperintense on T2W and/or arterial phase with persistent delayed enhancement). Sensitivity was 88% and specificity 100%. However, some HCA remained unclassifiable by MRI: HCA remodeled by necrotic/hemorrhagic changes covering > 50% of the lesion, H-HCAs without steatosis, IHCAs without SD, β-catenin-mutated and unclassified HCAs. Regarding malignant transformation (5/116) and bleeding (24/116), none was observed when the HCA diameter was smaller than 5.2 cm and 4.2 cm, respectively.

CONCLUSION

Based on the largest series evaluated until now, we identified several non-described MRI features and propose new highly sensitive and specific MRI criteria. With the addition of these new features, 88% of the two main HCA subtypes could be identified.

KEY POINTS

• HNF1α-mutated hepatocellular adenomas (H-HCA) are characterized by the presence of fat and hypovascular pattern in MRI. • Inflammatory hepatocellular adenomas (I-HCA) are characterized by different patterns translating sinusoidal dilatation including the newly described crescent sign. • No MRI specific pattern was identified for β-catenin-mutated HCA (b-HCA).

Sexual dimorphism in hepatitis B and C and hepatocellular carcinoma

The incidence of viral hepatitis B or C (HBV/HCV) infection and hepatocellular carcinoma is higher in male compared to female populations, showing a faster disease progression and results in a worse overall survival. Indeed, women are in general better protected from viral infections and show a lower risk of death from malignant cancer in comparison to men. Females mount stronger innate and adaptive immune responses than males, and therefore, most of the autoimmune diseases occur predominantly in females. Next to occupational and/or behavioral factors, cellular and molecular differences between the two sexes contribute to this observation. In this review, we will discuss underlying mechanisms that are important for the observed sex-related differences in liver diseases. A better appreciation of these differences between the two sexes might be of value for better and gender-specific treatment options.

Hepatocellular adenoma: when and how to treat? Update of current evidence

Hepatocellular adenoma (HCA) is a rare, benign liver tumor. Discovery of this tumor is usually as an incidental finding, correlated with the use of oral contraceptives, or pregnancy. Treatment options have focused on conservative management for the straightforward, smaller lesions (<5 cm), with resection preferred for larger lesions (>5 cm) that pose a greater risk of hemorrhage or malignant progression. In recent years, a new molecular subclassification of HCA has been proposed, associated with characteristic morphological features and loss or increased expression of immunohistochemical markers. This subclassification could possibly provide considerable benefits in terms of patient stratification, and the selection of treatment options. In this review we discuss the decision-making processes and associated risk analyses that should be made based on lesion size, and subtype. The usefulness of this subclassification system in terms of the procedures instigated as part of the diagnostic work-up of a suspected HCA will be outlined, and suitable treatment schemes proposed.

[Hepatocellular tumours in noncirrhotic liver tissue]

In recent years, the spectrum of tissue-based diagnostics of hepatocellular tumours has changed due to novel molecular pathological findings. Innovative radiographics filter out small lesions and ambiguous tumours for bioptical sampling. The spectrum of these tumours includes hepatocellular carcinoma, hepatocellular adenomas, focal nodular hyperplasia and macroregenerative nodules. Primarily, morphological analysis should identify the dignity of a lesion. After exclusion of HCC and reactive liver cell nodules, hepatocellular adenomas should be further subclassified based on immunohistochemical/molecular pathological criteria according to the WHO classification of liver tumours. This procedure provides significant additional information regarding the prognosis and therapeutic implications of hepatocellular adenomas.

Current Proceedings in the Molecular Dissection of Hepatocellular Adenomas: Review and Hands-on Guide for Diagnosis

Molecular dissection of hepatocellular adenomas has brought forward a diversity of well-defined entities. Their distinction is important for routine practice, since prognosis is tightly related to the individual subgroup. Very recent activity has generated new details on the molecular background of hepatocellular adenoma, which this article aims to integrate into the current concepts of taxonomy.

Progression of non-alcoholic steatosis to steatohepatitis and fibrosis parallels cumulative accumulation of danger signals that promote inflammation and liver tumors in a high fat-cholesterol-sugar diet model in mice

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is becoming a pandemic. While multiple 'hits' have been reported to contribute to NAFLD progression to non-alcoholic steatohepatitis (NASH), fibrosis and liver cancer, understanding the natural history of the specific molecular signals leading to hepatocyte damage, inflammation and fibrosis, is hampered by the lack of suitable animal models that reproduce disease progression in humans. The purpose of this study was first, to develop a mouse model that closely mimics progressive NAFLD covering the spectrum of immune, metabolic and histopathologic abnormalities present in human disease; and second, to characterize the temporal relationship between sterile/exogenous danger signals, inflammation, inflammasome activation and NAFLD progression.

METHODS

Male C57Bl/6 mice were fed a high fat diet with high cholesterol and a high sugar supplement (HF-HC-HSD) for 8, 27, and 49 weeks and the extent of steatosis, liver inflammation, fibrosis and tumor development were evaluated at each time point.

RESULTS

The HF-HC-HSD resulted in liver steatosis at 8 weeks, progressing to steatohepatitis and early fibrosis at 27 weeks, and steatohepatitis, fibrosis, and tumor development at 49 weeks compared to chow diet. Steatohepatitis was characterized by increased levels of MCP-1, TNFα, IL-1β and increased liver NASH histological score. We found increased serum levels of sterile danger signals, uric acid and HMGB1, as early as 8 weeks, while endotoxin and ATP levels increased only after 49 weeks. Increased levels of these sterile and microbial danger signals paralleled upregulation and activation of the multiprotein complex inflammasome. At 27, 49 weeks of HF-HC-HSD, activation of M1 macrophages and loss of M2 macrophages as well as liver fibrosis were present. Finally, similar to human NASH, liver tumors occurred in 41% of mice in the absence of cirrhosis and livers expressed increased p53 and detectable AFP.

CONCLUSIONS

HF-HC-HSD over 49 weeks induces the full spectrum of liver pathophysiologic changes that characterizes the progression of NAFLD in humans. NAFLD progression to NASH, fibrosis and liver tumor follows progressive accumulation of sterile and microbial danger signals, inflammasome activation, altered M1/M2 cell ratios that likely contribute to NASH progression and hepatic tumor formation.

Hepatocellular adenoma with malignant transformation in male patients with non-cirrhotic livers

Introduction

Hepatocellular adenomas (HCAs), with a risk of malignant transformation into hepatocellular carcinoma (HCC), classically develop in young women who are taking oral contraceptives. It is now clear that HCAs may also occur in men. However, it is rarely reported that HCAs with malignant transformation occur in male patients with non-cirrhotic livers. This study aimed to characterize the malignancy of HCAs occurring in male patients.

Methods

All patients with HCAs with malignant transformation who underwent hepatectomy at the Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between January 1, 1999 and December 31, 2011 were enrolled in the study. The clinical characteristics as well as radiologic and pathologic data were reviewed.

Results

HCAs with malignant transformation were observed in 5 male patients with non-cirrhotic livers, but not in female patients. The alpha-fetoprotein (AFP) levels were higher in patients with HCAs with malignant transformation than in patients with HCAs without malignant transformation. The diameters of the tumors with malignant transformation were larger than 5 cm in 3 cases and smaller than 5 cm in 2 cases. The 5 patients were all alive without recurrence by the end of the study period. The disease-free survival times of the 5 patients were 26, 48, 69, 69, and 92 months.

Conclusion

Our results indicate that resection would be advised even if the presumptive diagnosis is adenoma smaller than 5 cm in diameter, especially in male patients.

Hepatocellular adenoma management: advances but still a long way to go

Hepatocellular adenomas (HCAs) are composed of four molecular subgroups: mutations inactivating the HNF1A gene; the inflammatory phenotype with mutations of different genes leading to STAT3 activation; the activation of β-catenin by mutations in exon 3; among β-HCA, half display both inflammatory and β-catenin-activated phenotypes; and the unclassified tumors. The identification of these subtypes by MRI and immunohistochemistry on tissue is considered as a major criterion to manage patients. Of particular relevance is the identification of the β-catenin-mutated group due to its high risk of malignant transformation. In spite of this progress, the classification has not gained recognition among surgeons. It is hoped that by working as a multidisciplinary team, including surgeons, radiologists, pathologists and molecular biologists, patients will be managed more rationally. In this article, we will present known and new data, well accepted and that which is still controversial. The progress made in the field of HCA in the last 12 years, whether in epidemiology, diagnosis (clinical, pathology, imaging) or management, is related in one way or another to molecular advances.

Lymphoepithelioma-like hepatocellular carcinoma: an uncommon variant of hepatocellular carcinoma with favorable outcome

Lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC) is an uncommon variant of HCC with only 22 cases reported in the literature. To better determine the incidence, clinicopathologic features, prognostic significance, and molecular pathogenesis of LEL-HCC, we presented the largest series of LEL-HCC from a 9-year retrospective cohort of patients with HCC undergoing surgical resection. LEL-HCC was identified in 20 patients (4.9%). Compared with patients having HCC without significant tumor-infiltrating lymphocyte (TIL), patients with LEL-HCC had a relatively lower frequency of male sex (P=0.022), tended to present at early-stage disease (80.0% vs. 56.3% as AJCC stage I, P=0.037; 100% vs. 77.3% as BCLC stage 0/A, P=0.010), and all harbored a solitary tumor only (P=0.006). There was no significant difference in the age at presentation, underlying chronic liver disease, cirrhotic background, serum α-fetoprotein level, tumor size, histologic grade, and frequencies of vascular invasion. Most of the TILs in LEL-HCC were cytotoxic T lymphocytes. None of the LEL-HCCs was associated with Epstein-Barr virus. LEL-HCC was associated with better overall (5-y survival: 94.1% vs. 63.9%; P=0.007) and progression-free (5-y survival: 87.8% vs. 46.6%; P=0.002) survivals compared with HCC without significant TIL. The multivariate analysis revealed that LEL-HCC was an independent prognostic factor for overall and progression-free survivals. The adjusted hazard ratio of cancer death and tumor progression for LEL-HCC was 0.12 (P=0.037) and 0.14 (P=0.002), respectively. LEL-HCC did not differ in frequencies of microsatellite instability, BRAF mutation, and DNA hypermethylation. In brief, LEL-HCC is a distinct uncommon variant of HCC characterized by dense cytotoxic T-cell infiltration and favorable prognosis.

Gene mutations in hepatocellular adenomas

Hepatocellular adenomas (HCA) are rare, benign liver tumours that often occur in women of reproductive age. HCA has been associated with the use of oral contraceptives, but the increased incidence of the tumour in older women and in men has linked the tumour type to other diseases, including the metabolic syndrome. Genotypical classification of the adenomas has led to the identification of four subgroups that correlate genotype with phenotype: human hepatocyte nuclear factor-1 alpha (HNF1α) inactivating HCA, β-catenin activating HCA, inflammatory HCA and unclassified HCA. HNF1α inactivating HCA is associated with bi-allelic mutations in the TCF1 gene and morphologically has marked steatosis. β-catenin activating HCA has increased activity of the Wnt/β-catenin pathway and is associated with possible malignant transformation. Inflammatory HCA is characterized by an oncogene-induced inflammation due to alterations in the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. In the diagnostic setting, sub classification of HCA is based primarily on immunohistochemical analyzes, and has had an increasing impact on choice of treatment and individual prognostic assessment. This review offers an overview of the reported gene mutations associated with hepatocellular adenomas together with a discussion of the diagnostic and prognostic value.

Inflammatory hepatocellular adenomas can mimic focal nodular hyperplasia on gadoxetic acid-enhanced MRI

OBJECTIVE

Inflammatory hepatocellular adenoma (HCA) is a recently categorized entity of hepatocellular neoplasms. We investigated whether gadoxetic acid-enhanced MRI can distinguish inflammatory HCA from focal nodular hyperplasia (FNH).

MATERIALS AND METHODS

From January 1, 2009, through January 1, 2013, gadoxetic acid-enhanced MRI examinations from two institutions were reviewed for HCA, with specific histologic features of inflammatory HCA. Biopsy and resection slides were reviewed, and immunohistochemistry for glutamine synthetase was performed in a subset to confirm the initial diagnosis.

RESULTS

A total of 10 possible cases of inflammatory HCA were identified in the pathology database. On the basis of glutamine synthetase staining performed for this study, three cases were rediagnosed as FNH and thus were excluded from the study. Therefore, a total of seven patients with inflammatory HCA were identified. On gadoxetic acid-enhanced MRI, four of these patients had classic features of FNH (group A, FNH mimics), and three had imaging features suggestive of HCA (group B, typical inflammatory HCA). Imaging features that were considered diagnostic of FNH included isointense or minimal T2 hyperintensity, arterial enhancement, and diffuse hyperintensity on hepatobiliary phase. Three of the four patients with FNH mimics had slides available for pathologic rereview, and the diagnosis of inflammatory HCA was supported by glutamine synthetase immunohistochemistry findings. The pathology reports of the remaining four cases were rereviewed and were also found to have features consistent with inflammatory HCA.

CONCLUSION

Inflammatory HCA can mimic FNH on MRI, including hepatobiliary phase hyperintensity. Moreover, conventional pathology using histopathology alone may lead to misclassification of inflammatory HCA.