Two case reports of childhood liver cell adenomas harboring beta-catenin abnormalities

The Genetic Changes of Hepatoblastoma

Hepatoblastoma is the most common malignant liver cancer in childhood. The etiology of hepatoblastoma remains obscure. Hepatoblastoma is closely related to genetic syndromes, hinting that hepatoblastoma is a genetic predisposition disease. However, no precise exposures or genetic events are reported to hepatoblastoma occurrence. During the past decade, significant advances have been made in the understanding of etiology leading to hepatoblastoma, and several important genetic events that appear to be important for the development and progression of this tumor have been identified. Advances in our understanding of the genetic changes that underlie hepatoblastoma may translate into better patient outcomes. Single nucleotide polymorphisms (SNPs) have been generally applied in the research of etiology's exploration, disease treatment, and prognosis assessment. Here, we reviewed and discussed the molecular epidemiology, especially SNPs progresses in hepatoblastoma, to provide references for future studies and promote the study of hepatoblastoma's etiology.

Clinicopathological features and post-resection outcomes of hepatocellular adenoma

Backgrounds/Aims

Hepatocellular adenomas (HCA) are rare benign liver tumors with the potential of malignant transformation and risk of bleeding. We investigated the clinicopathological features and outcomes of HCA in 19 patients who underwent surgical resection.

Methods

This retrospective observational study included 19 patients who underwent hepatic resection during a 9-year period from 2011 to 2019.

Results

The incidence of HCA was 0.18% of all hepatic resection cases during the study period. The mean age of the patients was 34.3±9.6 years, and 12 patients (63.2%) were female. Abdominal pain was present as initial clinical manifestation in 5 patients and the other 14 patients had no specific symptoms. HCA was diagnosed in 7 out of 8 patients who underwent liver biopsy. R0 resection was performed in 18 patients (94.7%) and laparoscopic liver resection was performed in 11 patients (57.9%). The mean tumor size was 5.6±3.6 cm and 17 patients had a single tumor. Immunohistochemical analysis of the resected tumor specimens revealed hepatocyte-nuclear-factor-1α mutated HCA in 2 (10.5%), β-catenin-mutated HCA in 2 (10.5%), inflammatory HCA in 12 (63.2%) and unclassified HCA in 3 (15.8%). There were no pathognomonic findings in the preoperative liver imaging studies among these four groups. Currently, all patients are alive with a mean follow-up period of 40.1±26.3 months. One patient showed residual tumors after incomplete resection.

Conclusions

Surgical resection may be indicated if imaging studies show diagnostic ambiguity, growing tumor or symptomatic mass. Because of the risk of tumor recurrence and malignant transformation, long-term follow-up is necessary.

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.

Hepatocellular adenoma classification: a comparative evaluation of immunohistochemistry and targeted mutational analysis

BACKGROUND

Four subtypes of hepatocellular adenomas (HCA) are recognized: hepatocyte-nuclear-factor-1α mutated (H-HCA), β-catenin-mutated type with upregulation of glutamine synthetase (b-HCA), inflammatory type (IHCA) with serum-amyloid-A overexpression, and unclassified type. Subtyping may be useful since b-HCA appear to have higher risk of malignant transformation. We sought to apply subtype analysis and assess histological atypia, correlating these with next-generation sequencing analysis.

METHODS

Twenty-six HCA were stained with serum amyloid A (SAA), liver fatty acid-binding protein (LFABP), glutamine synthetase (GS), and β-catenin IHC, followed by analysis with a targeted multiplex sequencing panel.

RESULTS

By IHC, 4 HCA (15.4 %) were classified as b-HCA, 11 (42.3 %) as IHCA, 9 (34.6 %) as H-HCA, and two (7.7 %) unclassifiable. Eight HCA (30.8 %) showed atypia (3 b-HCA, 4 IHCA and 1 H-HCA). Targeted sequencing confirmed HNF1A mutations in all H-HCA, confirming reliability of LFABP IHC in identifying these lesions. CTNNB1 mutations were detected in 1 of 4 (25 %) of GS/β-catenin-positive cases, suggesting that positive GS stain does not always correlate with CTNNB1 mutations.

CONCLUSIONS

Immunohistochemistry does not consistently identify b-HCA. Mutational analysis improves the diagnostic accuracy of β-catenin-mutated HCA and is an important tool to assess risk of malignancy in HCA.

Hepatocellular adenoma containing hepatocellular carcinoma in a male patient with familial adenomatous polyposis coli: Report of a case

Hepatocellular adenoma (HCA) is a benign condition occurring most frequently in young women using oral contraceptives. We herein report the first case of a 28-year-old man with familial adenomatous polyposis (FAP) who experienced hepatocellular carcinoma (HCC) within HCA. A preoperative computed tomography scan of the abdomen disclosed a tumor measuring 5.8 cm in diameter in the left lobe of the liver. A total proctocolectomy with construction of a linear stapled J-pouch, a hand-sewn ileoanal anastomosis and a liver tumor resection were performed. The pathology of the resected specimen confirmed the diagnosis of HCA containing HCC. Five cases of HCA have been reported that developed in patients with FAP, but this is the first case of HCA containing HCC. Hepatocellular adenomas occur due to the inactivation of hepatic nuclear factor 1α, but the mechanism underlying the malignant transformation from HCA to HCC could not be identified in this case.

Recent developments in liver pathology

CONTEXT

Hepatocellular carcinoma is the sixth most common malignancy and the third leading cause of cancer deaths worldwide, making pathologic identification of precursor lesions essential. Recent molecular genetic, pathologic, and clinical data have led to the stratification of hepatic adenomas into subgroups with unique molecular profiles and varying potential for malignant transformation, as well as to the reclassification of telangiectatic focal nodular hyperplasia as telangiectatic adenoma. Clinical, morphologic, and molecular genetic studies have also established juvenile hemochromatosis and pediatric nonalcoholic steatohepatitis as entities distinct from their adult counterparts.

OBJECTIVE

To review the recent molecular genetic characterization of telangiectatic hepatic adenomas and juvenile hemochromatosis, as well as the recent clinicopathologic characterization of pediatric nonalcoholic steatohepatitis.

DATA SOURCES

Literature review, personal experience, and material from the University of Chicago.

CONCLUSIONS

Basic science and translational research have led to the classification of many pathologic entities of the liver according to molecular genetic and protein expression profiles that correspond to traditional morphologic categories. Insights into signal transduction pathways that are activated in, and protein expression patterns unique to, an individual disease may lead to the development of new therapeutic agents and novel diagnostic biomarkers.

Molecular pathogenesis of focal nodular hyperplasia and hepatocellular adenoma

Focal nodular hyperplasia (FNH) and hepatocellular adenomas (HCAs) are benign tumors that occur in otherwise normal liver parenchyma. FNH is considered to be the result of a hyperplastic response to increased blood flow secondary to vascular malformations. Most FNH are polyclonal and to date, the molecular pathway and mechanisms that are altered in FNH have yet to be elucidated. In contrast, HCAs are consistently monoclonal tumors, which have been divided up into three subtypes of tumors depending on the molecular alteration detected in the tumors: HNF1alpha inactivation, beta-catenin activation and/or an acute inflammatory response in the tumor. These molecular features are closely related to clinical and pathological characteristics, and one of the most critical correlations is the higher risk of malignant transformation for beta-catenin activated HCA cases. Moreover, various risk factors, such as oral contraception and obesity, are associated with HCA occurrence and may collaborate with constitutional genetic predisposition related to HNF1alpha or CYP1B1 germline mutations. Altogether, the recent identification of different molecular pathways that contribute to tumor development has significantly increased our knowledge of benign hepatocellular tumorigenesis. These findings may modify our clinical practice, particularly in the diagnosis and follow-up of HCA patients.

[Hepatocellular adenoma. Malignancy potential and differentiation from hepatocellular carcinoma]

In contrast to hepatocellular carcinoma (HCC), very few molecular pathological studies have been carried out on hepatocellular adenoma (HCA). Particularly from the surgical point of view, based on views passed on verbally and in the literature of the 1970s and 1980s, a possible degeneration of the HCA provides grounds for operating. Published cases of transitions from HCA into HCC were evaluated on the basis of today's morphological standards. A comparison was made between the patterns of new molecular pathological studies of HCA, above all the work of our own groups, and those of HCC. The results speak against the suggestion that a typical solitary HCA in pre-menopausal women is a precursor lesion of HCC. After a critical review of the literature, only one casuistic case of a transition of HCA to HCC under a hormone therapy, which is no longer practiced today, remained. A limitation of particular HCA in genetic and metabolic diseases, children, adult males, adenomatosis, and HCA-like tumors with known risk factors of HCC would seem pragmatically meaningful. With classic HCA, however, the oncological indication for surgery does not apply. A prerequisite is a histological clarification, if necessary with the support of molecular pathological methods.

Genotype-phenotype correlation in hepatocellular adenoma: new classification and relationship with HCC

Hepatocellular adenomas are benign tumors that can be difficult to diagnose. To refine their classification, we performed a comprehensive analysis of their genetic, pathological, and clinical features. A multicentric series of 96 liver tumors with a firm or possible diagnosis of hepatocellular adenoma was reviewed by liver pathologists. In all cases, the genes coding for hepatocyte nuclear factor 1alpha (HNF1alpha) and beta-catenin were sequenced. No tumors were mutated in both HNF1alpha and beta-catenin enabling tumors to be classified into 3 groups, according to genotype. Tumors with HNF1alpha mutations formed the most important group of adenomas (44 cases). They were phenotypically characterized by marked steatosis (P < 10(-4)), lack of cytological abnormalities (P < 10(-6)), and no inflammatory infiltrates (P < 10(-4)). In contrast, the group of tumors defined by beta-catenin activation included 13 lesions with frequent cytological abnormalities and pseudo-glandular formation (P < 10(-5)). The third group of tumors without mutation was divided into two subgroups based on the presence of inflammatory infiltrates. The subgroup of tumors consisting of 17 inflammatory lesions, resembled telangiectatic focal nodular hyperplasias, with frequent cytological abnormalities (P = 10(-3)), ductular reaction (P < 10(-2)), and dystrophic vessels (P = .02). In this classification, hepatocellular carcinoma associated with adenoma or borderline lesions between carcinoma and adenoma is found in 46% of the beta-catenin-mutated tumors whereas they are never observed in inflammatory lesions and are rarely found in HNF1alpha mutated tumors (P = .004). In conclusion, the molecular and pathological classification of hepatocellular adenomas permits the identification of strong genotype-phenotype correlations and suggests that adenomas with beta-catenin activation have a higher risk of malignant transformation.

Overexpression of regenerating islet-derived 1 alpha and 3 alpha genes in human primary liver tumors with β-catenin mutations

The Wnt/beta-catenin signaling pathway is activated in many human hepatocellular carcinomas (HCC). We tried to identify the genes involved in carcinogenesis and progression of HCC with beta-catenin mutations. We used PCR-based subtractive hybridization to compare gene expression between malignant and benign components of a human HCC occurring in pre-existing adenoma activated for beta-catenin. Two of the genes identified belong to the Regenerating gene (REG) family. They encode the Regenerating islet-derived 3 alpha (REG3A/HIP/PAP/REG-III) and 1 alpha (REG1A) proteins, both involved in liver and pancreatic regeneration and proliferation. Using siRNA directed against beta-catenin, we demonstrated that REG3A is a target of beta-catenin signaling in Huh7 hepatoma cells. The upregulation of REG3A and REG1A expression is significantly correlated to the beta-catenin status in 42 HCC and 28 hepatoblastomas characterized for their beta-catenin status. Thus, we report strong evidence that both genes are downstream targets of the Wnt pathway during liver tumorigenesis.

Liver cell adenoma and liver cell adenomatosis

During the last three decades liver cell adenoma and liver cell adenomatosis have emerged as new clinical entities in hepato-logical practice due to the widespread use of oral contraceptives and increased imaging of the liver. On review of published series there is evidence that 10% of liver cell adenomas progress to hepatocellular carcinoma, diagnosis is best made by open or laparoscopic excision biopsy, and the preferred treatment modality is resection of the liver cell adenoma to prevent bleeding and malignant transformation. In liver cell adenomatosis, the association with oral contraceptive use is not as high as in solitary liver cell adenomas. The risk of malignant transformation is not increased compared with solitary liver cell adenomas. Treatment consists of close monitoring and imaging, resection of superficially located, large (>4 cm) or growing liver cell adenomas. Liver transplantation is the last resort in case of substantive concern about malignant transformation or for large, painful adenomas in liver cell adenomatosis after treatment attempts by liver resection.

Congenital extrahepatic portocaval shunt (Abernethy type 2), huge liver mass, and patent ductus arteriosus--a case report of its rare clinical presentation in a young girl

The authors report a case of congenital extrahepatic portocaval shunt with a hypoplastic portal vein. This type of shunt is called an Abernethy type 2 shunt, where the portal vein and inferior vena cava are connected side to side, and a hypoplastic portal flow exists in the liver parenchyma. This case of a young girl is complicated with a cardiac anomaly and a large hyperplastic nodule in the liver. This phenotype usually is seen in the Abernethy type 1 shunt, which is a side-to-end shunt with the complete absence of a portal vein. In this context, the current case is very unique in its clinical manifestation, and this phenotype has never been reported. Therefore, it is important to speculate the etiology and treatment of this kind of abnormality and its associated hepatic mass.