Pediatric liver tumors: initial presentation, image finding and outcome

Hepatic tumors in Iranian children: Characteristics and survival predictors

BACKGROUND

Hepatic tumors are rare in children. This study was conducted to determine the characteristics of liver masses in children and identify the independent predictors of their survival.

METHODS

Medical records of children aged <18 years with a confirmed diagnosis of hepatic tumor diagnosed between January 2008 and December 2023 at two referral centers affiliated to Shiraz University of Medical Sciences, southern Iran, were reviewed.

RESULTS

There were 153 children with hepatic tumors. The median age of the patients was 2 (IQR, 1-5) years. Abdominal pain and distension, and presence of a palpable mass and fever were the most common signs and symptoms at presentation. The most common tumor was hepatoblastoma (64.5 %) followed by hepatocellular carcinoma (HCC, 9.9 %). Right hepatectomy and hepatic segmentectomy were the most common surgical approach used. Children with hepatoblastoma were significantly (p < 0.001) younger than those with HCC. The risk of hepatoblastoma in males was twice that in females. Jaundice was not common in those with hepatoblastoma but it was in HCC. About a quarter of patients died. After adjusting for covariates, abdominal pain (adj OR = 4.90) and distension (adj OR = 3.17), and a diagnosis of HCC (adj OR = 13.63) were independent predictors of a poor prognosis.

CONCLUSIONS

The characteristics of pediatric hepatic tumors in our study were similar to those reported in most studies. Abdominal pain and distension and presence of HCC or jaundice were independent predictors of a poor prognosis.

Genome-wide mapping of cancer dependency genes and genetic modifiers of chemotherapy in high-risk hepatoblastoma

A lack of relevant genetic models and cell lines hampers our understanding of hepatoblastoma pathogenesis and the development of new therapies for this neoplasm. Here, we report an improved MYC-driven hepatoblastoma-like murine model that recapitulates the pathological features of embryonal type of hepatoblastoma, with transcriptomics resembling the high-risk gene signatures of the human disease. Single-cell RNA-sequencing and spatial transcriptomics identify distinct subpopulations of hepatoblastoma cells. After deriving cell lines from the mouse model, we map cancer dependency genes using CRISPR-Cas9 screening and identify druggable targets shared with human hepatoblastoma (e.g., CDK7, CDK9, PRMT1, PRMT5). Our screen also reveals oncogenes and tumor suppressor genes in hepatoblastoma that engage multiple, druggable cancer signaling pathways. Chemotherapy is critical for human hepatoblastoma treatment. A genetic mapping of doxorubicin response by CRISPR-Cas9 screening identifies modifiers whose loss-of-function synergizes with (e.g., PRKDC) or antagonizes (e.g., apoptosis genes) the effect of chemotherapy. The combination of PRKDC inhibition and doxorubicin-based chemotherapy greatly enhances therapeutic efficacy. These studies provide a set of resources including disease models suitable for identifying and validating potential therapeutic targets in human high-risk hepatoblastoma.

Incidental Liver Lesions in children: A practical and evidence-based approach

Incidental liver lesions are increasingly being discovered in the context of the increased use of ultrasound studies and the majority are benign. In children, although individually rare, the differential diagnosis is broad and therefore a systematic approach is of utmost importance to reduce the radiological and disease burden in children and their families. This review article collected current evidence and provides fundamental information for the clinician regarding specific differential diagnoses and unique imaging features of benign liver lesions in children. Ultimately, we propose a practical stepwise approach mainly involving clinical and radiological workup. Laboratory tests and histopathological examination may be necessary in the presence of red flags or in indeterminate lesions.

[Imaging of hepatic tumors in children and adolescents]

BACKGROUND

Pediatric liver tumors are relatively rare, but thorough knowledge of their imaging features is still important.

OBJECTIVES

Frequency and imaging features of benign and malignant liver masses during childhood and adolescence.

MATERIALS AND METHODS

Discussion of relevant original articles, review manuscripts and expert recommendations concerning imaging of childhood liver tumors.

RESULTS

The most common malignant tumors of the liver are hepatoblastoma, which usually occur in younger children, as well as in some regions hepatocellular carcinoma. In contrast to most benign masses, such as focal nodular hyperplasia, simple cysts or fatty liver infiltrations, their imaging morphology is not very characteristic. Radiologically, sonography and magnetic resonance imaging (MRI) are used for assessment. Both methods benefit from intravenous contrast agent administration.

CONCLUSIONS

Childhood liver tumors show a broad spectrum of morphological manifestations. Some entities can be characterized using standard imaging, some require multimodal imaging or histological assessment. In addition to morphological imaging criteria, age and the medical history as well as laboratory data play an important role in establishing the correct diagnosis.

Diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) v2017 in predicting malignant liver lesions in pediatric patients: a preliminary study

BACKGROUND

Liver Imaging Reporting and Data System (LI-RADS) has standardized the evaluation of hepatic lesions in adults at risk of developing hepatocellular carcinoma (HCC). There is no accepted imaging algorithm for diagnosing HCC in the pediatric population.

OBJECTIVE

The aim of our study was to evaluate the diagnostic accuracy and inter-rater reliability of LI-RADS version 2017 (v2017) for diagnosing HCC in a pediatric cohort.

MATERIALS AND METHODS

This retrospective, Institutional Review Board-approved study involved review of all abdominal dynamic contrast-enhanced imaging at a tertiary children's hospital during a 10-year period, yielding 151 liver lesions in patients <18 years. Cases with active extrahepatic malignancy or an inadequate reference standard were excluded. Two readers independently evaluated all included hepatic lesions using LI-RADS criteria. Pathology and imaging follow-up were used as reference standards.

RESULTS

A total of 41 lesions in 41 patients met criteria for evaluation (3 HCCs, 8 non-HCC malignancies, 30 benign lesions). A LI-RADS designation of definite HCC had high sensitivity (Reader 1/Reader 2: 100%, 95% confidence interval [CI] 31-100%) and high specificity (Reader 1: 84%, 95% CI: 68-93%; Reader 2: 97%, 95% CI: 85-100%) for predicting HCC. However, positive predictive value was only 33% (95% CI: 9-69%) and 75% (95% CI: 22-99%) for Reader 1 and Reader 2, respectively. For predicting any type of hepatic malignancy, a LI-RADS designation of definitely or likely malignant (i.e. not necessarily HCC) had a sensitivity of 100% (95% CI: 74-100%) and 90% (95% CI: 61-100%) for Reader 1 and Reader 2, respectively, and a negative predictive value (NPV) of 100% (95% CI: 81-100%) and 96% (95% CI: 83-99%) for Reader 1 and Reader 2, respectively. Interobserver agreement was substantial for the overall LI-RADS category (weighted κ=0.62; 95% CI: 0.38-0.86).

CONCLUSION

The positive predictive value of LI-RADS v2017 for diagnosing HCC was limited by the low frequency of HCC among pediatric patients. However, a LI-RADS designation of definitely or likely malignant had high sensitivity and NPV for any type of hepatic malignancy and may serve to direct clinical management by selecting patients for tissue sampling.

Malignant tumors of the liver in children

This article aims to give an overview of pediatric liver tumors; in particular of the two most frequently occurring groups of hepatoblastomas and hepatocellular carcinomas. Focus lays on achievements gained through worldwide collaboration. We present recent advances in insight, treatment results, and future questions to be asked. Increasing international collaboration between the four major Pediatric Liver Tumor Study Groups (SIOPEL/GPOH, COG, and JPLT) may serve as a paradigm to approach rare tumors. This international effort has been catalyzed by the Children's Hepatic tumor International Collaboration (CHIC) formation of a large collaborative database. Interrogation of this database has led to a new universal risk stratification system for hepatoblastoma using PRETEXT/POSTTEXT staging as a backbone. Pathologists in this international collaboration have established a new histopathological consensus classification for pediatric liver tumors. Concomitantly there have been advances in chemotherapy options, an increased role of liver transplantation for unresectable tumors, and a web portal system developed at www.siopel.org for international education, consultation, and collaboration. These achievements will be further tested and validated in the upcoming Paediatric Hepatic International Tumour Trial (PHITT).

Pre-S2 deletion mutants of hepatitis B virus could have an important role in hepatocarcinogenesis in Asian children

Although many studies on the risk factors and their carcinogenesis in adult hepatocellular carcinoma (HCC) have been reported, they remain poorly understood in childhood HCC. A retrospective study of 42 HCC cases in Asian children was conducted. Hepatitis B virus (HBV)-DNA in HCC tissues was detected in 36 of 42 (86%) cases tested, while no hepatitis C virus (HCV)-RNA was detectable in any of HCCs. Twenty of 36 (56%) HCC cases were accompanied by cirrhosis. Surprisingly, very high prevalence of the HBV pre-S deletion mutant was recognized in 27 of 30 (90%) HCCs examined. They occurred most frequently in pre-S2 (20/27, 74%) followed by pre-S1 (5/27, 18.5%), and both pre-S1/S2 (2/27, 7.4%). Interestingly, the pre-S2 mutant consistently appeared with deletion at nt 4-57 in all of the 20 cases with the pre-S2 mutant (100%) and within this locus in the two cases with both pre-S-1/S2 mutants. Type II ground-glass hepatocytes in non-tumorous livers were seen in 15 of the 22 HCCs with the pre-S2 deletion mutant (68%). This hotspot mutation in the pre-S2 was further confirmed by complete genomic sequence of HBV in a Japanese boy who eventually developed HCC. Our result strongly suggests that HBV is a major contributor to the development of HCC in Asian children. The HBV pre-S2 deletion mutant at nt 4-57 which has a CD8 T-cell epitope could be responsible for the emergence and aggressive outcome of childhood HCC. Determination of this hotspot mutation in the pre-S2 region could be a useful index for predicting the clinical outcome of HCC development.

Focal liver diseases in neonatal and pediatric liver transplant candidates: a pictorial essay

The aim of this review is to present the wide spectrum of common and uncommon focal liver diseases affecting neonatal and pediatric liver transplant candidates, analyzed using ultrasonography (US), 16- or 64-multidetector row helical CT (MDCT) and 1.5-T magnetic resonance (MR) fast imaging. Correlation of imaging findings and explanted liver or histology is illustrated in representative cases. Associated uncommon congenital anomalies are shown.

Sex hormone influence on hepatitis in young male A/JCr mice infected with Helicobacter hepaticus

Hepatitis B virus (HBV), the leading cause of human hepatocellular carcinoma, is especially virulent in males infected at an early age. Likewise, the murine liver carcinogen Helicobacter hepaticus is most pathogenic in male mice infected before puberty. We used this model to investigate the influence of male sex hormone signaling on infectious hepatitis. Male A/JCr mice were infected with H. hepaticus or vehicle at 4 weeks and randomized into surgical and pharmacologic treatment groups. Interruption of androgen pathways was confirmed by hormone measurements, histopathology, and liver gene and Cyp4a protein expression. Castrated males and those receiving the competitive androgen receptor antagonist flutamide had significantly less severe hepatitis as determined by histologic activity index than intact controls at 4 months. Importantly, the powerful androgen receptor agonist dihydrotestosterone did not promote hepatitis. No effect on hepatitis was evident in males treated with the 5alpha-reductase inhibitor dutasteride, the peroxisome proliferator-activated receptor-alpha agonist bezafibrate, or the nonsteroidal anti-inflammatory drug flufenamic acid. Consistent with previous observations of hepatitis-associated liver-gender disruption, transcriptional alterations involved both feminine (cytochrome P450 4a14) and masculine (cytochrome P450 4a12 and trefoil factor 3) genes, as well gender-neutral (H19 fetal liver mRNA, lipocalin 2, and ubiquitin D) genes. Hepatitis was associated with increased unsaturated C(18) long-chain fatty acids (oleic acid and linoleic acid) relative to saturated stearic acid. Our results indicate that certain forms of androgen interruption can inhibit H. hepaticus-induced hepatitis in young male mice, whereas androgen receptor agonism does not worsen disease. This raises the possibility of targeted hormonal therapy in young male patients with childhood-acquired HBV.

Malignant hepatic tumor occurring 10 yrs after a histocompatible sibling donor bone marrow transplantation for severe aplastic anemia

A 13-yr-old boy developed post-transplant liver tumor. At three yrs of age, this patient underwent a histocompatible sibling donor BMT for severe aplastic anemia, after a conditioning with antithymocyte globulin and cyclophosphamide. He became a HBV carrier after BMT. Stable mixed chimerism and mild thrombocytopenia, but no active hepatitis continued. At age 13, abdominal pain was a sign of massive tumor. Extremely high levels of alpha-fetoprotein indicated the clinical diagnosis of hepatoblastoma that might be the first report as post-BMT malignancy. The necropsy specimens revealed that the tumor was recipient cell-origin and showed the histopathological features of both hepatoblastoma and hepatocellular carcinoma. Prolonged mixed chimerism and hepatitis virus infection might induce a rare oncogenesis after non-irradiated conditioning.