Hepatocellular malignant neoplasm, NOS: a clinicopathological study of 11 cases from a single institution

A 6-year-old boy with an atypical liver neoplasm harboring a novel RPS6KA3 variant

Pediatric hepatoblastoma (HBL) and hepatocellular carcinoma (HCC) are primary liver malignant neoplasms with 5-year event-free survival of >80% and <30%, respectively. In these patients, α-fetoprotein levels can guide surgical intervention and monitor disease progression. Although histology and immunohistochemical stains support diagnosis, genetic testing can elucidate mechanisms that drive pathogenesis. Pediatric HBL and HCC harbor well-characterized molecular signatures such as alterations in CTNNB1, TERT, and AXIN1 that alter the Wnt/β-catenin pathway. Approximately 8% of individuals with HCC harbor RPS6KA3 variants that appear with other gene mutations. Herein, we report a novel solitary pathogenic RPS6KA3 variant finding in a 6-year-old boy whose final diagnosis was hepatocellular malignant neoplasm, not otherwise specified.

Comparative Clinicopathologic and Genomic Analysis of Hepatocellular Neoplasm, Not Otherwise Specified, and Hepatoblastoma

Accurate diagnosis and treatment of hepatocellular neoplasm, not otherwise specified (HCN-NOS), poses significant challenges. Our study aimed to investigate the clinicopathologic and genomic similarities and differences between HCN-NOS and hepatoblastoma (HB) to guide diagnostic and treatment strategies. The clinicopathologic characteristics of 16 patients with HCN-NOS and 23 patients with HB were compared. Molecular studies, including the OncoKids DNA- and RNA-based next-generation sequencing panel, chromosomal microarray, and targeted Sanger sequencing analyses of CTNNB1 and TERT promoters, were employed. We found that patients with HCN-NOS were older (P < .001) and more frequently classified as high risk (P < .01), yet they showed no significant differences in alpha fetoprotein levels or survival outcomes compared with those with HB. HCN-NOS and HB had a comparable frequency of sequence variants, with CTNNB1 mutations being predominant in both groups. Notably, TERT promoter mutations (37.5%) and rare clinically significant variants (BRAF, NRAS, and KMT2D) were exclusive to HCN-NOS. HCN-NOS demonstrated a higher prevalence of gains in 1q, encompassing the MDM4 locus (17/17 vs 11/24; P < .001), as well as loss/loss of heterozygosity (LOH) of 1p (11/17 vs 6/24; P < .05) and chromosome 11 (7/17 vs 1/24; P < .01) when compared with HB. Furthermore, the recurrent loss/LOH of chromosomes 3, 4p, 9, 15q, and Y was only observed in HCN-NOS. However, no significant differences were noted in gains of chromosomes 2, 8, and 20, or loss/LOH of 4q and 11p between the 2 groups. Notably, no clinically significant gene fusions were detected in either group. In conclusion, our study reveals that HCN-NOS exhibits high-risk clinicopathologic features and greater structural complexity compared with HB. However, patients with HCN-NOS exhibit comparable alpha fetoprotein levels at diagnosis, CTNNB1 mutation rates, and survival outcomes when subjected to aggressive treatment, as compared with those with HB. These findings have the potential to enhance diagnostic accuracy and inform more effective treatments for HCN-NOS.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part I

Malignant focal liver lesions (FLLs) are commonly reported in adults but rarely seen in the pediatric population. Due to the rarity, the understanding of these diseases is still very limited. In children, most malignant FLLs are congenital. It is very important to choose appropriate imaging examination concerning various factors. This paper will outline common pediatric malignant FLLs, including hepatoblastoma, hepatocellular carcinoma, and cholangiocarcinoma and discuss them against the background of the latest knowledge on comparable/similar tumors in adults. Medical imaging features are of vital importance for the non-invasive diagnosis and follow-up of treatment of FLLs in pediatric patients. The use of CEUS in pediatric patients for characterizing those FLLs that remain indeterminate on conventional B mode ultrasounds may be an effective option in the future and has great potential to be integrated into imaging algorithms without the risk of exposure to ionizing radiation.

Potential methylation-regulated genes and pathways in hepatocellular neoplasm, not otherwise specified

Background and Aims

The molecular basis of hepatocellular neoplasm, not otherwise specified (HCN-NOS) is unknown. We aimed to identify gene expression patterns, potential methylation-regulated genes and pathways that characterize the tumor, and its possible relationship to hepatoblastoma and hepatocellular carcinoma (HCC).

Approach & Results

Parallel genome-wide profiling of gene expression (RNAseq) and DNA methylation (EPIC850) was performed on 4 pairs of pre-treatment HCN-NOS tumors and adjacent non-tumor controls. 2530 significantly differentially expressed genes (DEGs) were identified between tumors and controls. Many of these DEGs were associated with hepatoblastoma and/or HCC. Analysis Match in Ingenuity Pathway Analysis determined that the gene expression profile of HCN-NOS was unique but significantly similar to that of both hepatoblastoma and HCC. A total of 27,195 CpG sites (CpGs) were significantly differentially methylated (DM) between tumors and controls, with a global hypomethylation pattern and predominant CpG island hypermethylation in promotor regions. Aberrant DNA methylation predominated in Developmental Process and Molecular Function Regulator pathways. Embryonic stem cell pathways were significantly enriched. In total, 1055 aberrantly methylated (at CpGs) and differentially expressed genes were identified, including 25 upstream regulators and sixty-one potential CpG island methylation-regulated genes. Eight methylation-regulated genes (TCF3, MYBL2, SRC, HMGA2, PPARGC1A, SLC22A1, COL2A1 and MYCN) had highly consistent gene expression patterns and prognostic value in patients with HCC, based on comparison to publicly available datasets.

Conclusions

HCN-NOS has a unique, stem-cell like gene expression and DNA methylation profile related to both hepatoblastoma and HCC but distinct therefrom. Further, 8 methylation-regulated genes associated with prognosis in HCC were identified.

International Society of Paediatric Surgical Oncology (IPSO) Surgical Practice Guidelines

Most children with tumors will require one or more surgical interventions as part of the care and treatment, including making a diagnosis, obtaining adequate venous access, performing a surgical resection for solid tumors (with staging and reconstruction), performing procedures for cancer prevention and its late effects, and managing complications of treatment; all with the goal of improving survival and quality of life. It is important for surgeons to adhere to sound pediatric surgical oncology principles, as they are closely associated with improved local control and survival. Unfortunately, there is a significant disparity in survival rates in low and middle income countries, when compared to those from high income countries. The International Society of Paediatric Surgical Oncology (IPSO) is the leading organization that deals with pediatric surgical oncology worldwide. This organization allows experts in the field from around the globe to gather and address the surgical needs of children with cancer. IPSO has been invited to contribute surgical guidance as part of the World Health Organization Initiative for Childhood Cancer. One of our goals is to provide surgical guidance for different scenarios, including those experienced in High- (HICs) and Low- and Middle-Income Countries (LMICs). With this in mind, the following guidelines have been developed by authors from both HICs and LMICs. These have been further validated by experts with the aim of providing evidence-based information for surgeons who care for children with cancer. We hope that this initiative will benefit children worldwide in the best way possible. Simone Abib, IPSO President Justin T Gerstle, IPSO Education Committee Chair Chan Hon Chui, IPSO Secretary.

The Emerging Influences of Alpha-Fetoprotein in the Tumorigenesis and Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide, and its mortality rate is the third-highest, after lung cancer and colorectal cancer. Currently, systematic targeted therapies for HCC mainly include multiple kinase inhibitors and immunotherapy. However, these drugs carry a black-box warning about the potential for inducing severe toxicity, and they do not significantly prolong the survival period of patients due to the highly heterogeneous characteristics of HCC etiology. In order to improve the prediction, effective treatment and prognosis of HCC, the tools and different biomarkers in clinical practices are recommended. Alpha-fetoprotein (AFP) is the earliest and the most widely used serum marker in the detection of HCC. Interestingly, serum AFP and cytoplasmic AFP show different, even opposite, roles in the cancer progression of HCC. This review focuses on biological characteristics, regulatory mechanisms for gene expression, emerging influences of AFP in HCC and its possible implications in HCC-targeted therapy.

Pediatric Liver Tumors: Updates in Classification

Malignant primary liver tumors are rare in children. Yet a wide histologic spectrum is seen, particularly in hepatoblastoma, the most common malignant liver tumor in children. Furthermore, there can be significant morphologic overlap with hepatocellular carcinoma, the second most common pediatric liver malignancy, and tumors with hybrid features of hepatoblastoma and hepatocellular carcinoma are also reported (currently placed in the provisional category of malignant hepatocellular neoplasm, not otherwise specified). This review provides detailed morphologic descriptions and updates in the evolving clinical context of these tumors, and presents recent molecular advances that may further help in accurate classification of these tumors, which is critical in their management.

Imaging and clinical features of pediatric hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is rare in children and there is limited data on its imaging features.

OBJECTIVE

To describe imaging features of pediatric HCC and correlate them with clinical and laboratory findings.

MATERIALS AND METHODS

We retrospectively reviewed imaging in all pediatric HCC cases seen between January 2000 and January 2019. Imaging features defined in LI-RADS (Liver Imaging Reporting and Data System) and tumor extent by PRETEXT (pretreatment extent of disease) criteria were noted by two radiologists. Patient charts were reviewed to collect clinical features, alpha-fetoprotein (AFP) level and pathology findings.

RESULTS

Of the 15 children (7 boys, 8 girls; mean age: 11.8 years, age range: 6-17 years) included in the study, 12/15 had computed tomography, 9/15 had magnetic resonance imaging and 9/15 had ultrasound exams available for review. Pathological types of HCC included classic (11/15, 73%), fibrolamellar (3/15, 20%) and mixed cholangiocarcinoma-HCC (1/15, 7%). Eighty percent occurred de novo in normal liver and 67% showed elevated AFP levels. Arterial phase hyperenhancement was seen in 83% of cases, washout in 86%, capsule in 50% and tumor-in-vein in 33%. The mean tumor size was 9.8 cm and 40% were multifocal on imaging. Staging revealed PRETEXT II tumors in 47%, III in 20% and IV in 33%. There were no PRETEXT I tumors. The two most common PRETEXT annotation factors were portal vein and caudate lobe involvement in 71% and 43% of cases, respectively. Fibrolamellar HCC demonstrated central scar, normal AFP levels and normal background liver.

CONCLUSION

Pediatric HCC are large heterogeneous tumors, as reflected by high PRETEXT staging, and commonly include portal vein and caudate involvement. This affects resectability of these tumors at presentation. Central scar, normal AFP level and normal liver background may help differentiate fibrolamellar HCC from other types of HCC.

Liver Tumors in Pediatric Patients

The most recent advance in the care of children diagnosed with hepatoblastoma and hepatocellular carcinoma is the Pediatric Hepatic International Tumor Trial, which opened to international enrollment in 2018. It is being conducted as a collaborative effort by the pediatric multicenter trial groups in North America, Europe, and the Far East. This international effort was catalyzed by a new unified global risk stratification system for hepatoblastoma, an international histopathologic consensus classification for pediatric liver tumors, and a revised 2017 collaborative update of the PRE-Treatment EXTent of disease radiographic based staging system.

Hepatocellular Malignant Neoplasm, Not Otherwise Specified: A New Name in Liver Tumors: A Brief Narrative Review of Published Cases

Background

Hepatocellular malignant neoplasm, not otherwise specified (HEM, NOS), is a rare liver tumor that is most commonly seen in adolescents. To the best of our knowledge, there has been no published review on this rare tumor in the English literature so far.

Summary

In this review, we will discuss all reported details, including demographic findings, clinical presentations, molecular histogenesis, imaging, gross pathology and histopathology, immunohistochemical findings, treatment modalities, and outcome, of the published cases of HEM, NOS, in the liver.

Key Message

Twenty-two cases of HEM, NOS, have been reported in the last 10 years in the English literature. This tumor produces a large liver mass and is characteristically seen in adolescents presenting with right upper quadrant pain. Histologically, HEM, NOS, is a nonbiliary hepatocytic tumor with a biphasic pattern, that is, a mixture of 2 components of hepatocellular carcinoma and hepatoblastoma (HBL). There is no characteristic immunohistochemical feature for this tumor. Imaging findings are also not specific. Treatment of this tumor needs extensive surgery or even liver transplantation. Most of the cases in the literature were treated with the primary diagnosis of HBL, so pathologists, onco-surgeons, and oncologists should get familiar with this tumor to provide better treatment options. More case series with more follow-ups are necessary for the definite determination of the outcome of this tumor as a unique entity.

Contrast-enhanced ultrasound of benign and malignant liver lesions in children

Contrast-enhanced ultrasound (CEUS) is increasingly being used in children. One of the most common referrals for CEUS performance is characterization of indeterminate focal liver lesions and follow-up of known liver lesions. In this setting, CEUS is performed with intravenous administration of ultrasound contrast agents (UCAs). When injected into a vein, UCA microbubbles remain confined within the vascular network until they dissipate. Therefore, visualization of UCA within the tissues and lesions corresponds to true blood flow. CEUS enables continuous, real-time observation of the enhancement pattern of a focal liver lesion, allowing in most cases for a definite diagnosis and obviating the need for further cross-sectional imaging or other interventional procedures. The recent approval of Lumason (Bracco Diagnostics, Monroe Township, NJ) for pediatric liver CEUS applications has spurred the widespread use of CEUS. In this review article we describe the role of CEUS in pediatric liver applications, focusing on the examination technique and interpretation of main imaging findings of the most commonly encountered benign and malignant focal liver lesions. We also compare the diagnostic performance of CEUS with other imaging modalities for accurate characterization of focal liver lesions.

Rare malignant liver tumors in children

Malignant hepatic tumors in children are rare, comprising 1.3% of all pediatric malignancies. Following hepatoblastoma, hepatocellular carcinoma is the second most common. Other malignant hepatic tumors seen in childhood include those of mesenchymal origin including undifferentiated embryonal sarcoma, angiosarcoma, rhabdomyosarcoma and epithelioid hemangioendothelioma, as well as biliary tumors such as cholangiocarcinoma. Diagnosis can be challenging because of their rarity, and the recognition of distinctive imaging features for certain tumors such as epithelioid hemangioendothelioma and biliary rhabdomyosarcoma can focus the differential diagnosis and expedite the diagnostic process. A complete MRI examination with hepatocyte-specific contrast media and diffusion-weighted imaging helps to focus the differential diagnosis, and, although findings are often nonspecific, in some cases typical features on MRI can be helpful in diagnosis. Histopathological analysis is usually required for definitive diagnosis. Hepatic tumors tend to be aggressive, and full staging is imperative to establish disease extent. Significant proportions are not amenable to upfront surgical resection and often require a multimodality approach including neoadjuvant chemotherapy within a multidisciplinary setting. Facilitating complete surgical resection is usually required for better survival. In this review, we emphasize pathology and imaging features for rare liver tumors that are useful in reaching a prompt diagnosis. We also discuss general clinical findings, prognosis and management of these tumors.

Successful treatment of a metastatic hepatocellular malignant neoplasm, not otherwise specified with chemotherapy and liver transplantation

Hepatocellular malignant neoplasm, not otherwise specified (HCN-NOS) is a provisional entity describing a subset of rare malignant pediatric liver tumors with overlapping features of hepatoblastoma and hepatocellular carcinoma. We present a case illustration of metastatic HCN-NOS successfully treated with a backbone of hepatoblastoma chemotherapy, pulmonary metastastectomy, and liver transplantation, along with a literature review of the clinical outcomes of HCN.

cHCC-CCA: Consensus terminology for primary liver carcinomas with both hepatocytic and cholangiocytic differentation

Primary liver carcinomas with both hepatocytic and cholangiocytic differentiation have been referred to as "combined (or mixed) hepatocellular-cholangiocarcinoma." These tumors, although described over 100 years ago, have attracted greater attention recently because of interest in possible stem cell origin and perhaps because of greater frequency and clinical recognition. Currently, because of a lack of common terminology in the literature, effective treatment and predictable outcome data have been challenging to accrue. This article represents a consensus document from an international community of pathologists, radiologists, and clinicians who have studied and reported on these tumors and recommends a working terminology for diagnostic and research approaches for further study and evaluation.

CONCLUSION

It is recommended that diagnosis is based on routine histopathology with hematoxylin and eosin (H&E); immunostains are supportive, but not essential for diagnosis. (Hepatology 2018;68:113-126).