Staging and Restaging Pediatric Abdominal and Pelvic Tumors: A Practical Guide.

The most common abdominal malignancies diagnosed in the pediatric population include neuroblastoma, Wilms tumor, hepatoblastoma, lymphoma, germ cell tumor, and rhabdomyosarcoma. There are distinctive imaging findings and patterns of spread for each of these tumors that radiologists must know for diagnosis and staging and for monitoring the patient's response to treatment. The multidisciplinary treatment group that includes oncologists, surgeons, and radiation oncologists relies heavily on imaging evaluation to identify the best treatment course and prognostication of imaging findings, such as the image-defined risk factors for neuroblastomas, the PRETreatment EXtent of Disease staging system for hepatoblastoma, and the Ann Arbor staging system for lymphomas. It is imperative for radiologists to be able to correctly indicate the best imaging methods for diagnosis, staging, and restaging of each of these most prevalent tumors to avoid inconclusive or unnecessary examinations. The authors review in a practical manner the most updated key points in diagnosing and staging disease and assessing response to treatment of the most common pediatric abdominal tumors. ©RSNA, 2024 Supplemental material is available for this article.

An indocyanine green-based liquid biopsy test for circulating tumor cells for pediatric liver cancer.

BACKGROUND: Hepatoblastoma and HCC are the most common malignant hepatocellular tumors seen in children. The aim of this study was to develop a liquid biopsy test for circulating tumor cells (CTCs) for these tumors that would be less invasive and provide real-time information about tumor response to therapy. METHODS: For this test, we utilized indocyanine green (ICG), a far-red fluorescent dye used clinically to identify malignant liver cells during surgery. We assessed ICG accumulation in cell lines using fluorescence microscopy and flow cytometry. For our CTC test, we developed a panel of liver tumor-specific markers, including ICG, Glypican-3, and DAPI, and tested it with cell lines and noncancer control blood samples. We then used this panel to analyze whole-blood samples for CTC burden with a cohort of 15 patients with hepatoblastoma and HCC and correlated with patient characteristics and outcomes. RESULTS: We showed that ICG accumulation is specific to liver cancer cells, compared to nonmalignant liver cells, non-liver solid tumor cells, and other nonmalignant cells, and can be used to identify liver tumor cells in a mixed population of cells. Experiments with the ICG/Glypican-3/DAPI panel showed that it specifically tagged malignant liver cells. Using patient samples, we found that CTC burden from sequential blood samples from the same patients mirrored the patients' responses to therapy. CONCLUSIONS: Our novel ICG-based liquid biopsy test for CTCs can be used to specifically detect and quantify CTCs in the blood of pediatric patients with liver cancer.

Predicting response of hepatoblastoma primary lesions to neoadjuvant chemotherapy through contrast-enhanced computed tomography radiomics.

OBJECTIVE: To investigate the clinical value of contrast-enhanced computed tomography (CECT) radiomics for predicting the response of primary lesions to neoadjuvant chemotherapy in hepatoblastoma. METHODS: Clinical and CECT imaging data were retrospectively collected from 116 children with hepatoblastoma who received neoadjuvant chemotherapy. Tumor response was assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST). Subsequently, they were randomly stratified into a training cohort and a test cohort in a 7:3 ratio. The clinical model was constructed using univariate and multivariate logistic regression, while the radiomics model was developed based on selected radiomics features employing the support vector machine algorithm. The combined clinical-radiomics model incorporated both clinical and radiomics features. RESULTS: The area under the curve (AUC) for the clinical, radiomics, and combined models was 0.704 (95% CI: 0.563-0.845), 0.830 (95% CI: 0.704-0.959), and 0.874 (95% CI: 0.768-0.981) in the training cohort, respectively. In the validation cohort, the combined model achieved the highest mean AUC of 0.830 (95% CI 0.616-0.999), with a sensitivity, specificity, accuracy, precision, and f1 score of 72.0%, 81.1%, 78.5%, 57.2%, and 63.5%, respectively. CONCLUSION: CECT radiomics has the potential to predict primary lesion response to neoadjuvant chemotherapy in hepatoblastoma.

FOXM1 and CHD4 expression is associated with chemoresistance in hepatoblastoma.

Hepatoblastoma (HB) is the most common malignant liver tumor in childhood. Although pre-operative cisplatin (CDDP)-based chemotherapy is often used in cases of HB, about 20％ of HB patients exhibit resistance to CDDP. Forkhead box protein M1 (FOXM1) and chromo-domain-helicase-DNA-binding protein 4 (CHD4) have been associated with CDDP resistance in various tumors. We here analyzed the immunohistochemical expression of FOXM1 and CHD4 in HB specimens of 33 patients (mean age: 20 months) post-chemotherapy. The differentiation of specimens was assessed using the digital pathology software QuPath®, and then the relation between the FOXM1 or CHD4 expression and the differentiation and various other clinicopathological parameters was investigated. The histological type was epithelial in 19 cases (57.6%) and mixed epithelial and mesenchymal in 14 cases (42.4%). Nine cases had only a fetal component, 1 case had only an embryonal component, 22 cases had both fetal and embryonal components, and 1 case had no viable tumor. Both the FOXM1 and CHD4 immunoexpressions were found significantly more frequently in the embryonal than fetal components (p<0.0001 and p<0.0001, respectively). Regarding chemotherapy efficacy, the alpha-fetoprotein (AFP) level after chemotherapy was correlated with both the imaging shrinkage rate (R=-0.52) and histological residual rate (the percentage of the viable tumors of HB after chemotherapy)(R=0.62). High FOXM1 score was correlated with a high-postoperative AFP value (p<0.01) and a low AFP attenuation rate (p<0.05), but the FOXM1 score was not correlated with the imaging shrinkage rate (p=0.4418) or histological residual rate (p=0.4418). High CHD4 score showed a nonsignificant trend toward correlation with high postoperative AFP value (p=0.0849) and was not significantly correlated with the other parameters. Collectively, our results showed that FOXM1 expression may be useful in evaluating the response to CDDP-based chemotherapeutic regimens. Accurate measurement of FOXM1 expression by our scoring system using QuPath® is important in cases with mixed HB components of various differentiation levels.

Malignant melanoma in a 12-year-old boy 17 months after completing hepatoblastoma treatment.

BACKGROUND: Melanoma is rare as a secondary malignant neoplasm among childhood cancer survivors. CASE: We report a case of a 12-year-old boy who developed malignant melanoma with systemic metastases 17 months after completing treatment for hepatoblastoma. The diagnosis was made unexpectedly based on a bone marrow examination. The patient did not respond to immune checkpoint inhibitor therapy and died 6 weeks after being diagnosed with melanoma. Whole-exome sequencing to examine 103 genes associated with cancer predisposition did not identify any germ-line variants. CONCLUSION: This case study provides a unique example of melanoma in a childhood cancer survivor following hepatoblastoma treatment but does not identify any candidate variant to link hepatoblastoma and melanoma.

Intratumoral CXCR4hi neutrophils display ferroptotic and immunosuppressive signatures in hepatoblastoma.

Pediatric hepatoblastoma (HB) is the most common primary liver malignancy in infants and children. With great diversity and plasticity, tumor-infiltrating neutrophils were one of the most determining factors for poor prognosis in many malignant tumors. In this study, through bulk RNA sequencing for sorted blood and tumor-infiltrated neutrophils and comparison of neutrophils in tumor and para-tumor tissue by single-cell sequencing, we found that intratumoral neutrophils were composed of heterogenous functional populations at different development stages. Our study showed that terminally differentiated neutrophils with active ferroptosis prevailed in tumor tissue, whereas, in para-tumor, pre-fate naïve neutrophils were dominant and ferroptotic neutrophils dispersed in a broad spectrum of cell maturation. Gene profiling and in vitro T-cell coculture experiment confirmed that one of main functional intratumoral neutrophils was mainly immunosuppressive, which relied on the activation of ferroptosis. Combining the bulk RNA-seq, scRNA-seq data, and immunochemistry staining of tumor samples, CXCL12/CXCR4 chemotaxis pathway was suggested to mediate the migration of neutrophils in tumors as CXCR4 highly expressed by intratumoral neutrophils and its ligand CXCL12 expressed much higher level in tumor than that in para-tumor. Moreover, our study pinpointed that infiltrated CXCR4hi neutrophils, regardless of their differential distribution of cell maturation status in HB tumor and para-tumor regions, were the genuine perpetrators for immune suppression. Our data characterized the ferroptosis-dependent immunosuppression energized by intratumoral CXCR4 expression neutrophils and suggest a potential cell target for cancer immunotherapies.

The expression analysis of SerpinB9 in hepatoblastoma microenvironment.

PURPOSE: In this research, we analyzed the expression of serpinB9 in hepatoblastoma and investigated the factors which enhance its expression. METHOD: SerpinB9 expression in hepatoblastoma cell lines and macrophages co-cultured with each other or stimulated by anticancer agents was examined using RT-qPCR and western blotting. Immunohistochemistry for SerpinB9 in hepatoblastoma specimens was performed. Single-cell RNA-sequence data for hepatoblastoma from an online database were analyzed to investigate which types of cells express SerpinB9. RESULT: HepG2, a hepatoblastoma cell line, exhibited increased expression of SerpinB9 when indirectly co-cultured with macrophages. Immunohistochemistry for the specimens demonstrated that serpinB9 is positive not in hepatoblastoma cells but in macrophages. Single-cell RNA sequence analysis in tissues from hepatoblastoma patients showed that macrophages expressed SerpinB9 more than tumor cells did. Co-culture of macrophages with hepatoblastoma cell lines led to the enhanced expression of SerpinB9 in both macrophages and cell lines. Anticancer agents induced an elevation of SerpinB9 in hepatoblastomas cell lines. CONCLUSION: In hepatoblastoma, SerpinB9 is thought to be more highly expressed in macrophages and enhanced by interaction with hepatoblastoma cell.

Mutational signature, cancer driver genes mutations and transcriptomic subgroups predict hepatoblastoma survival.

BACKGROUND: Hepatoblastoma is the most frequent pediatric liver cancer. The current treatments lead to 80% of survival rate at 5 years. In this study, we evaluated the clinical relevance of molecular features to identify patients at risk of chemoresistance, relapse and death of disease. METHODS: All the clinical data of 86 children with hepatoblastoma were retrospectively collected. Pathological slides were reviewed, tumor DNA sequencing (by whole exome, whole genome or target) and transcriptomic profiling with RNAseq or 300-genes panel were performed. Associations between the clinical, pathological, mutational and transcriptomic data were investigated. RESULTS: High-risk patients represented 44% of our series and the median age at diagnosis was 21.9 months (range: 0-208). Alterations of the WNT/ß-catenin pathway and of the 11p15.5 imprinted locus were identified in 98% and 74% of the tumors, respectively. Other cancer driver genes mutations were only found in less than 11% of tumors. After neoadjuvant chemotherapy, disease-specific survival and poor response to neoadjuvant chemotherapy were associated with 'Liver Progenitor' (p = 0.00049, p < 0.0001) and 'Immune Cold' (p = 0.0011, p < 0.0001) transcriptomic tumor subtypes, SBS35 cisplatin mutational signature (p = 0.018, p = 0.001), mutations in rare cancer driver genes (p = 0.0039, p = 0.0017) and embryonal predominant histological type (p = 0.0013, p = 0.0077), respectively. Integration of the clinical and molecular features revealed a cluster of molecular markers associated with resistance to chemotherapy and survival, enlightening transcriptomic 'Immune Cold' and Liver Progenitor' as a predictor of survival independent of the clinical features. CONCLUSIONS: Response to neoadjuvant chemotherapy and survival in children treated for hepatoblastoma are associated with genomic and pathological features independently of the clinical features.

Cellular origin and molecular mechanisms of lung metastases in patients with aggressive hepatoblastoma.

BACKGROUND AND AIMS: Lung metastases are the most threatening signs for patients with aggressive hepatoblastoma (HBL). Despite intensive studies, the cellular origin and molecular mechanisms of lung metastases in patients with aggressive HBL are not known. The aims of these studies were to identify metastasis-initiating cells in primary liver tumors and to determine if these cells are secreted in the blood, reach the lung, and form lung metastases. APPROACH: We have examined mechanisms of activation of key oncogenes in primary liver tumors and lung metastases and the role of these mechanisms in the appearance of metastasis-initiating cells in patients with aggressive HBL by RNA-Seq, immunostaining, chromatin immunoprecipitation, Real-Time Quantitative Reverse Transcription PCR and western blot approaches. Using a protocol that mimics the exit of metastasis-initiating cells from tumors, we generated 16 cell lines from liver tumors and 2 lines from lung metastases of patients with HBL. RESULTS: We found that primary HBL liver tumors have a dramatic elevation of neuron-like cells and cancer-associated fibroblasts and that these cells are released into the bloodstream of patients with HBL and found in lung metastases. In the primary liver tumors, the ph-S675-ß-catenin pathway activates the expression of markers of cancer-associated fibroblasts; while the ZBTB3-SRCAP pathway activates the expression of markers of neurons via cancer-enhancing genomic regions/aggressive liver cancer domains leading to a dramatic increase of cancer-associated fibroblasts and neuron-like cells. Studies of generated metastasis-initiating cells showed that these cells proliferate rapidly, engage in intense cell-cell interactions, and form tumor clusters. The inhibition of ß-catenin in HBL/lung metastases-released cells suppresses the formation of tumor clusters. CONCLUSIONS: The inhibition of the ß-catenin-cancer-enhancing genomic regions/aggressive liver cancer domains axis could be considered as a therapeutic approach to treat/prevent lung metastases in patients with HBL.

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.

Pediatric Hepatoblastoma After Neoadjuvant Chemotherapy: Diagnostic Performance of MR in Staging POSTTEXT and Vascular Involvement.

BACKGROUND: The assessment of resectability after neoadjuvant chemotherapy of hepatoblastoma is dependent on Post-Treatment EXTENT of Disease (POSTTEXT) staging and its annotation factors P (portal venous involvement) and V (hepatic venous/inferior vena cava [IVC] involvement), but MR performance in assessing them remains unclear. PURPOSE: To assess the diagnostic performance of contrast-enhanced MR imaging for preoperative POSTTEXT staging and diagnosing vascular involvement in terms of annotation factors P and V in pediatric hepatoblastoma following neoadjuvant chemotherapy. STUDY TYPE: Retrospective. SUBJECTS: Thirty-five consecutive patients (17 males, median age, 24 months; age range, 6-98 months) with proven hepatoblastoma underwent preoperative MR imaging following neoadjuvant chemotherapy. FIELD STRENGTH/SEQUENCE: 3.0 T; T2-weighted imaging (T2WI), T2WI with fat suppression, diffusion weighted imaging, radial stack-of-the-star/Cartesian 3D Dixon T1-weighted gradient echo imaging. ASSESSMENT: Three radiologists independently assessed the POSTTEXT stages and annotation factors P and V based on the 2017 PRE/POSTTEXT system. The sensitivities and specificities were calculated for 1) diagnosing each POSTTEXT stage; 2) discrimination of stages III and IV (advanced) from those stages I and II (non-advanced) hepatoblastomas; and 3) annotation factors P and V. The combination of pathologic findings and surgical records served as the reference standard. STATISTICAL TESTS: Sensitivity, specificity, Fleiss kappa test. RESULTS: The sensitivity and specificity ranges for discriminating advanced from non-advanced hepatoblastomas were 73.3%-80.0% and 80.0%-90.0%, respectively. For annotation factor P, they were 66.7%-100.0% and 90.6%, respectively. For factor V, they were 75.0% and 67.7%-83.9%, respectively. There was excellent, substantial, and moderate agreement on POSTTEXT staging (Fleiss kappa = 0.82), factors P (Fleiss kappa = 0.64), and factors V (Fleiss kappa = 0.60), respectively. DATA CONCLUSION: MR POSTTEXT provides reliable discrimination between advanced and non-advanced tumors, and MR has moderate to excellent specificity at identifying portal venous and hepatic venous/IVC involvement. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Circ-CCT2 Activates Wnt/ß-catenin Signaling to Facilitate Hepatoblastoma Development by Stabilizing PTBP1 mRNA.

BACKGROUND & AIMS: Circ-CCT2 (hsa_circ_0000418) is a novel circular RNA that stems from the CCT2 gene. However, the expression of circ-CCT2 and its roles in hepatoblastoma are unknown. Our study aims to study the circ-CCT2 roles in hepatoblastoma development. METHODS: Hepatoblastoma specimens were collected for examining the expression of circ-CCT2, TAF15, and PTBP1. CCK-8 and colony formation assays were applied for cell proliferation analysis. Migratory and invasive capacities were evaluated through wound healing and Transwell assays. The interaction between circ-CCT2, TAF15, and PTBP1 was validated by fluorescence in situ hybridization, RNA pull-down, and RNA immunoprecipitation. SKL2001 was used as an agonist of the Wnt/ß-catenin pathway. A subcutaneous mouse model of hepatoblastoma was established for examining the function of circ-CCT2 in hepatoblastoma in vivo. RESULTS: Circ-CCT2 was significantly up-regulated in hepatoblastoma. Overexpression of circ-CCT2 activated Wnt/ß-catenin signaling and promoted hepatoblastoma progression, whereas knockdown of circ-CCT2 exerted opposite effects. Moreover, both TAF15 and PTBP1 were up-regulated in hepatoblastoma tissues and cells. TAF15 was positively correlated with the expression of circ-CCT2 and PTBP1 in hepatoblastoma. Furthermore, circ-CCT2 recruited and up-regulated TAF15 protein to stabilize PTBP1 mRNA and trigger Wnt/ß-catenin signaling in hepatoblastoma. Overexpression of TAF15 or PTBP1 reversed knockdown of circ-CCT2-mediated suppression of hepatoblastoma progression. SKL2001-mediated activation of Wnt/ß-catenin signaling reversed the anti-tumor effects of silencing of circ-CCT2, TAF15, or PTBP1. CONCLUSIONS: Circ-CCT2 stabilizes PTBP1 mRNA and activates Wnt/ß-catenin signaling through recruiting and up-regulating TAF15 protein, thus promoting hepatoblastoma progression. Our findings deepen the understanding of hepatoblastoma pathogenesis and suggest potential therapeutic targets.

Navigating relapsed hepatoblastoma: Predictive factors and surgical treatment strategy.

OBJECTIVE: Hepatoblastoma (HB) is the most common primary hepatic malignancy in childhood. Relapse occurs in more than 50% of high-risk patients with a high mortality due to ineffective salvage therapies. The purpose of this study is to identify risk factors for relapsed HB and predictors of survival in a single tertiary referral center. METHODS: A retrospective chart review showed 129 surgically treated HB patients from October 2004 to July 2020. Of the cohort, 22 patients presented with relapsed HB. Relapse was defined as re-appearance of malignancy after 4 weeks of normalized AFP and disappearance of all tumors on imaging. RESULTS: Patients with relapsed HB had a 5-year overall survival (OS) of 45.4% compared to 93.1% in those without relapse (p = 0.001). When comparing PRETEXT IV, microvascular invasion, metastatic disease, and age on multivariate logistic regression, only PRETEXT IV was an independent risk factor for relapsed HB with an OR of 2.39 (95% CI: 1.16-4.96; p = 0.019). Mixed epithelial and mesenchymal HB (12/19, 63.2%) was the most common histology of primary tumors while pure epithelial HB (13/15, 86.6%) was the most common relapsed histology. Combination of surgical and medical therapy for relapsed disease was predictive of survival with an HR of 16.3 (95% CI: 1.783-149.091; p = 0.013) compared to only chemotherapy. CONCLUSIONS: This study demonstrates that PRETEXT IV staging is an independent predictor of relapsed disease. The most common relapsed histology was epithelial, suggesting a potential selection or resistance of this component. Surgical resection is a critical component of multimodal therapy for relapsed HB.

Critical elements of pediatric liver cancer surgery.

The appropriate management of pediatric liver malignancies, primarily hepatoblastoma and hepatocellular carcinoma, requires an in depth understanding of contemporary preoperative risk stratification, experience with advanced hepatobiliary surgery, and a good relationship with one's local or regional liver transplant center. While chemotherapy regimens have become more effective, operative indications more well-defined, and overall survival improved, the complexity of liver surgery in small children provides ample opportunity for protocol violation, inadequate resection, and iatrogenic morbidity. These guidelines represent the distillation of contemporary literature and expert opinion as a means to provide a framework for preoperative planning and intraoperative decision-making for the pediatric surgeon.

Children's Oncology Group's 2023 blueprint for research: Liver tumors.

Liver tumors account for approximately 1%-2% of all pediatric malignancies, with the two most common tumors being hepatoblastoma (HB) and hepatocellular carcinoma (HCC). Previous Children's Oncology Group studies have meaningfully contributed to the current understanding of disease pathophysiology and treatment, laying groundwork for the ongoing prospective international study of both HB and HCC. Future work is focused on elucidating the biologic underpinnings of disease to support an evolution in risk categorization, advancements in the multidimensional care required to treat these patients, and the discovery of novel therapies.

Update on the Role of Imaging in Staging of Common Pediatric Abdominal Tumors.

Neuroblastoma, Wilms tumor, and hepatoblastoma are the most common pediatric abdominal malignancies. Management of these diseases is a multidisciplinary process that continues to evolve based on the results of international collaborative trials and advances in understanding of tumor biology. Each of these tumors has unique characteristics and behavior which are reflected in their respective staging systems. It is important for clinicians involved in the care of children with abdominal malignancies to be familiar with current staging guidelines and imaging recommendations. This article reviews the current role of imaging in the management of these common pediatric abdominal malignancies, with emphasis on initial staging.

Cytomorphology of paediatric hepatocellular carcinoma: A useful diagnostic adjunct.

INTRODUCTION: Hepatocellular carcinoma (HCC) is a common primary malignancy of the liver but is rare in the paediatric age group; thus, it may be misdiagnosed as the more common tumour, hepatoblastoma. Management varies in both these tumours, and pathological diagnosis thus plays an important role for definitive therapy. Only a few case reports available in the literature have described the cytological characteristics of paediatric HCC. The present study was thus planned to evaluate the cytomorphological features of paediatric HCC. METHODS: Cases diagnosed with HCC on ultrasound-guided fine needle aspiration cytology over a period of 14 years were retrieved. The cases were evaluated for detailed cytological features including cellularity, architecture, sinusoidal wrapping, trabecular thickness, necrosis, anisonucleosis, chromatin, nucleoli, nuclear contours, bi- or multinucleation, intranuclear and intracytoplasmic inclusions, naked nuclei, extra-medullary haematopoiesis, monomorphism, and nuclear overlapping. RESULTS: Twelve cases of HCC were included in the study. The median age at diagnosis was 10 years. Serum alpha-fetoprotein level was raised in most of them. Five of the 12 cases were characterised as moderately differentiated, three as poorly differentiated, two as well differentiated, and two as the fibrolamellar type of HCC. Cytohistological correlation was performed in seven cases. CONCLUSIONS: Ultrasound-guided fine needle aspiration serves as a useful tool to diagnose paediatric HCC and differentiate it from other primary hepatic malignancies, especially hepatoblastoma which closely mimics HCC in this age group, as serum alpha protein levels and imaging findings are unable to distinguish these two tumours.