Malignant transformation of hepatocellular adenoma

What is New in Pediatric Hepatic Neoplasms

The goal of this review is to provide a practical update on hepatic lesions affecting the pediatric population and is not meant to be an exhaustive summary of each entity. Hepatoblastoma is purposely not discussed as recent comprehensive reviews on this topic are available; instead, a discussion on rhabdoid tumor and the evolving concept of small cell undifferentiated hepatoblastoma and blastemal hepatoblastoma is included.

Upregulation of long noncoding RNAs LINC00941 and ABHD11-AS1 is associated with intrahepatic cholangiocarcinoma

ObjectiveMany long noncoding RNAs (lncRNAs) are associated with liver cancers, mainly hepatocellular carcinoma (HCC) and to a smaller extent intrahepatic cholangiocarcinoma (CCA). Most of such lncRNAs show similar dysregulation patterns when the two types of tumors are compared, suggesting that these aberrations are characteristic features of these liver tumor types. In the present study, we aimed to identify some candidate lncRNAs that are associated specifically with CCA.MethodsAccording to The Cancer Genome Atlas data, we chose LINC00941, ABHD11-AS1, and CASC8 as promising biomarkers dysregulated in CCA but unaffected in HCC. We first verified their upregulation in an existing transcriptomic dataset for CCA patients. Next, we estimated expression levels of these three lncRNAs by reverse-transcription quantitative PCR in a group of paired (tumorous/adjacent) postsurgery tissue samples from 110 patients with various liver lesions: CCA, HCC, combined HCC-CCA, or benign liver tumors.ResultsSignificant upregulation of LINC00941 and ABHD11-AS1 was noted in most of the investigated CCA samples, whereas in HCC samples, increased expression of these two lncRNAs was observed only in some types of cases (mainly characterized by an advanced tumor stage). In contrast, CASC8 manifested extremely low expression and no diagnostic potential in all the tested liver samples. Analyzing expression correlations of lncRNAs with candidate genes, we obtained strong evidence for LINC00941-mediated upregulation of CAPRIN2 in CCA.ConclusionsFor the first time, we show the upregulation of LINC00941 and ABHD11-AS1 in CCA and report their good potential as diagnostic biomarkers for this type of liver tumor.

Pathology and diagnostic approaches to well-differentiated hepatocellular lesions: a narrative review

Well-differentiated hepatocellular lesions (WDHLs) are liver tumors or nonneoplastic lesions in which the cells closely resemble normal hepatocytes. These lesions often include focal nodular hyperplasia, hepatocellular adenoma, macroregenerative nodule, dysplastic nodule, and well-differentiated hepatocellular carcinoma. The diagnosis of these lesions remains challenging because of their morphological similarities, particularly when examined using needle biopsy. The accurate diagnosis of WDHLs is crucial for patient management and prognosis. This review addresses the histopathological characteristics and diagnostic approaches of WDHLs.

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.

Update on the Pathology of Pediatric Liver Tumors: A Pictorial Review

Liver tumors in children are uncommon and show remarkable morphologic heterogeneity. Pediatric tumors may arise from either the epithelial or mesenchymal component of the liver and rarely may also show both lines of differentiation. Both benign and malignant liver tumors have been reported in children. The most common pediatric liver tumors by age are benign hepatic infantile hemangiomas in neonates and infants, malignant hepatoblastoma in infants and toddlers, and malignant hepatocellular carcinoma in teenagers. Here, we provide an up-to-date review of pediatric liver tumors. We discuss the clinical presentation, imaging findings, pathology, and relevant molecular features that can help in the correct identification of these tumors, which is important in managing these children.

Genetic and epigenetic analysis of hepatocellular adenomas with atypical morphological features

BACKGROUND

Hepatocellular adenoma (HCA) is a rare liver tumour, which can have atypical morphological features such as cytological atypia, pseudoglandular architecture, and altered reticulin framework. Little is known about the genetic and epigenetic alterations of such HCAs and whether they show the alterations classically found in hepatocellular carcinoma (HCC) or in HCA without atypical morphology.

METHODS

We analysed five HCAs with atypical morphological features and one HCA with transition to HCC. Every tumour was subtyped by immunohistochemistry, sequenced by a targeted NGS panel, and analysed on a DNA methylation microarray.

RESULTS

Subtyping of the five HCAs with atypical features revealed two β-catenin mutated HCA (b-HCA), two β-catenin mutated inflammatory HCA (b-IHCA), and one sonic hedgehog activated HCA (shHCA). None of them showed mutations typically found in HCC, such as, e.g. TERT or TP53 mutations. The epigenomic pattern of HCAs with atypical morphological features clustered with reference data for HCAs without atypical morphological features but not with HCC. Similarly, phyloepigenetic trees using the DNA methylation data reproducibly showed that HCAs with morphological atypia are much more similar to nonmalignant samples than to malignant samples. Finally, atypical HCAs showed no relevant copy number variations (CNV).

CONCLUSION

In our series, mutational, DNA methylation, as well as CNV analyses, supported a relationship of atypical HCAs with nonatypical HCAs rather than with HCC. Therefore, in cases with difficult differential diagnosis between HCC and HCA, it might be advisable to perform targeted sequencing and/or combined methylation/copy number profiling.

β-Catenin-activated inflammatory hepatocellular adenoma with pigmentation and atypical features: a case report

Hepatocellular adenomas are rare diseases, defined as benign liver neoplasms composed of cells with hepatocellular differentiation. Differential diagnosis of hepatocellular adenoma from other lesions, including focal nodular hyperplasia and hepatocellular carcinoma, is crucial to determine treatment strategy. We describe a case of β-catenin-activated inflammatory hepatocellular adenoma with malignant transformation. A 50-year-old man with a suspected liver tumor, based on abdominal ultrasonography findings, was referred to our hospital. Contrast-enhanced computed tomography and magnetic resonance imaging revealed a liver tumor in S2 which was enhanced in the arterial phase to the delayed phase. Based on diagnostic imaging findings, hepatocellular adenoma or focal nodular hyperplasia was suspected. We considered the possibility of malignant potential because of the enlargement of the lesion. Thus, we performed a laparoscopic hepatectomy. Histological examination showed pigment deposition in the hepatocytes, which was determined to be lipofuscin. Mild nuclear swelling and atypia in the tumor area indicated nodular growth. Based on the histological and immunohistochemical findings, the diagnosis was ꞵ-catenin-activated inflammatory hepatocellular adenoma with atypical features. The imaging features of hepatocellular adenoma and focal nodular hyperplasia are similar, but if the tumor tends to grow, surgical treatment should be performed because of the possibility of malignant hepatocellular adenoma.

Pathology of Combined Hepatocellular Carcinoma-Cholangiocarcinoma: An Update

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer that is composed of both hepatocellular and cholangiocellular differentiated cells. It is slightly more common in men and among Asian and Pacific islanders. Overall, risk factors are similar to classic risk factors of hepatocellular carcinoma (HCC). The classification has significantly evolved over time. The last WHO classification (2019) mainly emphasized diagnosis on morphological basis with routine stainings, discarded previously recognized classifications with carcinomas with stem cell features, introduced intermediate cell carcinoma as a specific subtype and considered cholangiolocarcinoma as a subtype of cholangiocellular carcinoma. Immunohistochemical markers may be applied for further specification but have limited value for diagnosis. Recent discoveries in molecular pathway regulation may pioneer new therapeutic approaches for this poor prognostic and challenging diagnosis.

A Rare Presentation of Multiple Hepatic Masses Due to Hepatic Adenoma: A Case Report

Hepatic adenomas (HAs) are rare but benign neoplasms of the liver which predominantly present as solitary lesions in women of reproductive age. The incidence of HAs has increased dramatically since the introduction of oral contraceptive pills (OCPs) along with the rising incidence of obesity. Discontinuation of OCPs and lifestyle modifications, including weight loss regimens, are considered as conservative treatment options for HAs. Large lesions may result in malignant transformation with a higher propensity for hemorrhage. Importantly, larger lesions that do not respond to conservative management require surgical excision. We report a case of a patient presenting with multiple hepatic lesions that were subsequently confirmed as HAs.

A Narrative Review on LI-RADS Algorithm in Liver Tumors: Prospects and Pitfalls

Liver cancer is the sixth most detected tumor and the third leading cause of tumor death worldwide. Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with specific risk factors and a targeted population. Imaging plays a major role in the management of HCC from screening to post-therapy follow-up. In order to optimize the diagnostic-therapeutic management and using a universal report, which allows more effective communication among the multidisciplinary team, several classification systems have been proposed over time, and LI-RADS is the most utilized. Currently, LI-RADS comprises four algorithms addressing screening and surveillance, diagnosis on computed tomography (CT)/magnetic resonance imaging (MRI), diagnosis on contrast-enhanced ultrasound (CEUS) and treatment response on CT/MRI. The algorithm allows guiding the radiologist through a stepwise process of assigning a category to a liver observation, recognizing both major and ancillary features. This process allows for characterizing liver lesions and assessing treatment. In this review, we highlighted both major and ancillary features that could define HCC. The distinctive dynamic vascular pattern of arterial hyperenhancement followed by washout in the portal-venous phase is the key hallmark of HCC, with a specificity value close to 100%. However, the sensitivity value of these combined criteria is inadequate. Recent evidence has proven that liver-specific contrast could be an important tool not only in increasing sensitivity but also in diagnosis as a major criterion. Although LI-RADS emerges as an essential instrument to support the management of liver tumors, still many improvements are needed to overcome the current limitations. In particular, features that may clearly distinguish HCC from cholangiocarcinoma (CCA) and combined HCC-CCA lesions and the assessment after locoregional radiation-based therapy are still fields of research.

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.

[Multiple hepatocellular adenomas and renal cell carcinoma associated with anabolic androgenic steroids]

The authors report a rare case of combination of chromophobe renal cell carcinoma Grade 2 pT2aN0 with multiple hepatocellular adenomas in a 31-year-old bodybuilder who received anabolic androgenic steroids at high doses for 8 years. According to MRI data, over 15 liver adenomas and tumor in the lower segment of the right kidney were detected. The patients underwent laparascopic resection of the right kidney and liver segments 2, 3 and 4 with large adenomas. Histological study and immunohistochemistry revealed no malignancy signs in hepatocellular adenomas. Nuclear β-catenin expression was absent. Kidney tumor had a structure of chromophobe renal cell carcinoma. The patient is currently being followed-up due to residual small liver adenomas. In our opinion, liver adenomatosis and renal cancer have the same cause in this case (chronic toxic effect of androgens).

Long-term outcomes following resection of hepatocellular adenomas with small foci of malignant transformation or malignant adenomas

BACKGROUND & AIMS

Malignant transformation of hepatocellular adenoma (MT-HCA) may occur in up to 5% of tumours. However, the prognostic value of this event remains poorly described. In this study, we aimed to analyse the long-term outcomes of patients undergoing liver resection (LR) for MT-HCA compared to those of patients resected for hepatocellular carcinoma (HCC) occurring on normal liver parenchyma (NP-HCC).

METHODS

This single-centre retrospective study included all patients who underwent LR for MT-HCA at Beaujon Hospital between 2001 and 2019. MT-HCAs were classified as small foci of malignant transformation HCA (SF-HCA) and as malignant HCA (M-HCA) in cases of predominant HCC foci. Recurrence-free survival (RFS) of MT-HCA was compared with that of NP-HCC after propensity score matching.

RESULTS

Forty patients (24 men, 16 women) underwent LR for MT-HCA, including 23 with SF-HCA and 17 with M-HCA. Of these cases, 16/40 (40%) had β-catenin mutations, 19/40 (47.5%) were inflammatory, 1 was HNF1α-mutated HCA and 4 (10%) were unclassified HCA. Microvascular invasion (12% vs. 0%, p = 0.091) and satellite nodules (25% vs. 4%, p = 0.028) were more frequently observed in M-HCA than in SF-HCA. After a median follow-up of 67 months, 10 (25%) patients with MT-HCA had tumour recurrence, including 9 with M-HCA and 1 with SF-HCA (p = 0.007). M-HCA was linked to significantly poorer 1-, 3-, 5- and 10-year RFS rates than SF-HCA (76%, 63%, 39%, 37% vs. 100%, 100%, 100%, 91%, p = 0.003). Multivariate analysis showed that SF-HCA was independently associated with improved RFS (hazard ratio 0.064; 95% CI 0.008-0.519; p = 0.01). After propensity score matching, NP-HCC was associated with significantly poorer 1-, 3-, 5- and 10-year RFS rates than MT-HCA (p = 0.01).

CONCLUSIONS

HCA with malignant transformation yields a better long-term prognosis than NP-HCC. Among MT-HCA, SF-HCA is associated with a better prognosis than M-HCA.

LAY SUMMARY

The prognostic relevance of malignant transformation of hepatocellular adenoma (HCA) remains unknown. Thus, the aim of our study was to compare the outcomes of patients undergoing liver resection for malignant transformation to those of patients undergoing liver resection for hepatocellular carcinoma (HCC). The main long-term risk after resection for carcinoma is recurrence. In this study, 10/40 patients with malignant transformation of HCA relapsed after resection and we identified age >55 years, presence of satellite nodes, and microvascular invasion as risk factors for long-term recurrence. Compared to patients with HCC, patients who underwent liver resection for HCA with malignant transformation had better long-term survival.

Hepatocellular Carcinoma Arising from Hepatocellular Adenoma in an Elderly Male Patient

Hepatocellular adenoma is a benign tumor of the liver occurring predominantly in young women taking oral contraceptives. The malignant transformation of hepatocellular adenoma into hepatocellular carcinoma has rarely been reported. Herein, we report the case of an elderly male patient with hepatocellular carcinoma that developed from hepatocellular adenoma. The patient's high risk for surgery and conflicting biopsy and imaging results made it difficult to determine the treatment direction. Eventually, the mass was completely removed by laparoscopic left hemi-hepatectomy without complications.

Pediatric Primary Hepatic Tumors: Diagnostic Considerations

The liver is the third most common site of abdominal tumors in children. This review article aims to summarize current evidence surrounding identification and diagnosis of primary hepatic tumors in the pediatric population based upon clinical presentation, epidemiology, and risk factors as well as classical imaging, histopathological, and molecular diagnostic findings. Readers will be able to recognize the features and distinguish between benign and malignant hepatic tumors within different age groups.

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.

Malignant transformation of liver fatty acid binding protein-deficient hepatocellular adenomas: histopathologic spectrum of a rare phenomenon

The molecular classification of hepatocellular adenomas highlights a distinctive genotype-phenotype correlation. Malignant transformation is an exceptionally rare complication of hepatocyte nuclear factor 1α (HNF1A)-inactivated hepatocellular adenomas. This subtype is characterized by loss of liver fatty acid binding protein immunoexpression. In this study, we characterized the histopathologic spectrum of 13 liver fatty acid binding protein-deficient hepatocellular adenoma cases showing malignant transformation from multiple centers. Clinicopathologic characteristics of these patients were evaluated. Stains for reticulin, liver fatty acid binding protein, beta-catenin and glutamine synthetase were applied to these lesions. Moreover, the findings were compared to patients with β-catenin mutated hepatocellular adenoma. Liver fatty acid binding protein-deficient hepatocellular adenomas with borderline features/carcinoma were seen predominantly in females (77%) with an average age of 46 ± 18 years and multiple lesions (77%; five patients with adenomatosis). Meanwhile, β-catenin mutated hepatocellular adenoma patients with malignant transformation were predominantly male (67%, p = 0.018) with single lesion (86%, p = 0.0009). The largest liver fatty acid binding protein-deficient hepatocellular adenoma nodule in each patient ranged from 4 to 15.5 cm. Loss of liver fatty acid binding protein by immunohistochemistry was noted in all adenoma and borderline/carcinoma components. Features of malignant transformation were pseudoglandular architecture (85%), cytologic atypia (85%), architectural atypia (100%) and lack of steatosis (100%). Other findings included myxoid change (39%), peliosis (46%) and sinusoidal dilatation (46%). Molecular studies confirmed somatic inactivation of HNF1A in 3 cases and absence of TERT promotor and exon 3 CTNNB1 mutations in five cases. To summarize, liver fatty acid binding protein-deficient hepatocellular adenoma with malignant transformation is most frequently seen in female patients with multiple lesions. Most of these lesions demonstrate pseudoglandular architecture, cytologic and architectural atypia, with lack of steatosis. The natural history of these lesions is relatively benign with the exception of disease recurrence in 1 patient.

A case of hepatocellular adenoma with pedunculated development and difficulty in diagnosis

Hepatocellular adenoma (HCA) is a benign hepatocyte-derived epithelial tumor. HCA is associated with oral contraceptive use among Caucasian populations. We report a case of hepatocellular adenoma with a pedunculated protuberance and high protein induced by vitamin K absence or antagonist-II (PIVKA-II) levels, which made diagnosis challenging. The patient was a 22-year-old woman. In a medical check-up, a high γ-GTP level was detected and a 115-mm solid mass was found in her lower abdomen via abdominal ultrasonography. A blood test showed a high PIVKA-II level. Abdominal CT showed a tumor in the lower abdomen. Contrast-enhanced CT showed a blood vessel thought to be the left hepatic artery connecting to the mass, and a blood vessel thought to be the left hepatic vein returning from the mass to the inferior vena cava. In EOB-MRI, uneven enhancement was observed after contrast imaging, but washout in the equilibrium phase was unclear. Parenchymal hepatocyte phases showed a pale, non-uniform, high signal. These findings indicated that the tumor was derived from the left lobe of the liver and was suggestive of HCC. Surgical resection was then performed. A pathological examination led to a diagnosis of HCA, corresponding to unclassified HCA. The WHO classification of tumors of the digestive system based on an immunohistological examination includes HNF1α-inactivated HCA, β-catenin-activated HCA, inflammatory HCA, and unclassified HCA. In summary, our patient had a large HCA with pedunculated protrusion into the extrahepatic pelvic cavity. This case was challenging to diagnose because of abnormally high PIVKA-II levels, and it was resected laparoscopically.

Repeat surgery in HNF1alpha-inactivated adenomatosis

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Malignant transformation of hepatocellular adenoma in a young female patient after ovulation induction fertility treatment: A case report

BACKGROUND

Hepatocellular adenoma (HCA) is a rare benign liver tumor usually affecting young women with a history of prolonged use of hormonal contraception. Although the majority is asymptomatic, a low proportion may have significant complications such as bleeding or malignancy. Despite responding to the hormonal stimulus, the desire for pregnancy in patients with small HCA is not contraindicated. However, through this work we demonstrate that intensive hormonal therapies such as those used in the treatment of infertility can trigger serious complications

CASE SUMMARY

A 33-year-old female with a 10-year history of oral contraceptive use was diagnosed with a hepatic tumor as an incidental finding in an abdominal ultrasound. The patient showed no symptoms and physical examination was unremarkable. Laboratory functional tests were within normal limits and tests for serum tumor markers were negative. An abdominal magnetic resonance imaging (MRI) was performed, showing a 30 mm × 29 mm focal lesion in segment VI of the liver compatible with HCA or Focal Nodular Hyperplasia with atypical behavior. After a total of six years of follow-up, the patient underwent ovulation induction treatment for infertility. On a following MRI, a suspected malignancy was warned and hence, surgery was decided. The surgical specimen revealed malignant transformation of HCA towards trabecular hepatocarcinoma with dedifferentiated areas. There was non-evidence of tumor recurrence after three years of clinical and imaging follow-up.

CONCLUSION

HCAs can be malignant regardless its size and low-risk appearance on MRI when an ovultation induction therapy is indicated.

Use of Eovist in Pediatric Patients: Pearls and Pitfalls

Magnetic resonance imaging is excellent at characterizing pediatric hepatobiliary pathology. Noncontrast MRI is helpful due to T2 hyperintensity associated with bile, but contrast enhancement offers additional means of lesional characterization. In particular, hepatocyte-specific contrast agents such as gadoxetate disodium (Eovist) exhibit partial hepatobiliary excretion which may be leveraged in these contexts. In this review, we will discuss gadoxetate disodium usage, including a sample-imaging protocol, and demonstrate applications and limitations in the pediatric population.

Focal β-catenin mutation identified on formalin-fixed and paraffin-embedded inflammatory hepatocellular adenomas

The identification of hepatocellular adenoma (HCA) with mutation in exon 3 of the CTNNB1 gene encoding for β-catenin is clinically relevant due to a higher risk of malignant transformation. Inflammatory HCA (IHCA) can exhibit β-catenin activation (β-IHCA). We report two cases with multiple IHCA in which focal β-catenin activation has been found in one of the IHCA. In both cases, the diagnosis of IHCA was confirmed on the resected nodules by routine stains, immunohistochemical detection of C-reactive protein (CRP) and molecular biology on frozen material. An additional molecular analysis was performed on formalin-fixed paraffin-embedded (FFPE) material that showed focal glutamine synthetase (GS) staining, the surrogate marker of β-catenin activation. In case 1, it was a 1.8-cm area within the 7.5 cm IHCA, and in case 2 a small 0.3-cm area within a 1.8 cm resected IHCA located close to a larger IHCA, negative for GS. In both cases, nuclear β-catenin expression and decreased reticulin network were observed in the GS expressing foci, together with cholestasis and diffuse CD34 expression in case 1. Molecular analysis by pyrosequencing on FFPE material using the GS-stained slides as reference to select areas with/without positive staining revealed a CTNNB1 exon 3 mutation restricted to the areas exhibiting both positive GS and CRP expression, whereas wild-type CTNNB1 was found in areas showing only CRP staining. These two cases illustrate focal β-catenin activation that can occur within IHCAs. Additional data are needed to determine if β-catenin mutation is a secondary event in IHCA.

Hepatocellular adenoma: Classification, variants and clinical relevance

Hepatocellular adenomas are benign tumors with two major complications, bleeding and malignant transformation. The overall narrative of hepatocellular adenoma has evolved over time. Solitary or multiple hepatocellular developing in the normal liver of women of child bearing age exposed to oral contraceptives still represents the most frequent clinical context, however, new associations are being recognized. Hepatocellular adenoma is discovered on a background of liver diseases such as non-alcoholic steatohepatitis, vascular diseases, and alcoholic cirrhosis. Hepatocellular adenoma is also reported in men, young or older adults, and even in infants. On the morpho-molecular side, the great leap forward was the discovery that hepatocellular adenoma was not a single entity and that at least 3 different subtypes exist, with specific underlying gene mutations. These mutations affect the HNF1A gene, several genes leading to JAK/STAT3 pathway activation and the CTNNB1 gene. All of them are associated with more or less specific histopathological characteristics and can be recognized using immunohistochemistry either with specific antibodies or with surrogate markers. Liver pathologists and radiologists are the key actors in the identification of the different subtypes of hepatocellular adenoma by the recognition of their specific morphological features. The major impact of the classification of hepatocellular adenoma is to identify subjects who are at higher risk of malignant transformation. With the development of new molecular technologies, there is hope for a better understanding of the natural history of the different subtypes, and, particularly for their mechanisms of malignant transformation.

Malignant transformation of a β-catenin inflammatory adenoma due to an S45 β-catenin-activating mutation present 12 years before

In 1984, a 24-year-old woman underwent a right hepatectomy after a 17-cm nodule, diagnosed as a hepatocellular adenoma with some atypia. The resection was incomplete. Follow-up was interrupted. In 1996, a computed tomographic scan revealed a large multifocal hepatocellular carcinoma confirmed on biopsies. The patient died the same year. We reviewed these nodules using immunohistochemistry and gene sequencing. C-reactive protein was overexpressed in the tumor resected in 1984. Glutamine synthetase was heterogeneous in the tumor, with a few tumor nuclei expressing β-catenin. Glypican and heat shock protein 70 were negative. In this β-catenin-activated inflammatory hepatocellular adenoma, S45 β-catenin-activating mutation was detected on fixed tissue, embedded in paraffin without TERT promoter mutation. An identical CTNNB1 mutation was identified in the 1996 liver tumor together with a TERT promoter mutation showing that this hepatocellular carcinoma results from the malignant transformation of the initial β-catenin inflammatory adenoma.

[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.