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.

Malignant rhabdoid tumour of liver: Conundrum on ascitic fluid

Ascitic fluid analysis is an important tool for diagnosis and staging. Cytological analysis is routinely done as a part of workup for ascites. This is challenging in paediatric malignancies where multiple differentials need to be considered at times with limited cellularity. We present a case of malignant rhabdoid tumour of liver in a young child presenting with abdominal lump and ascites. The diagnosis was offered on ascitic fluid cytology based on cytomorphology, supporting immunohistochemistry and later confirmed on biopsy. This report briefly discusses its differentials and approach to diagnosis.

A Systematic Review and Meta-Analysis of Malignant Rhabdoid and Small Cell Undifferentiated Liver Tumors: A Rational for a Uniform Classification

Simple Summary

Malignant rhabdoid tumors of the liver are very rare pediatric liver tumors with a devastating prognosis. It is currently unclear which histological subtypes of pediatric liver tumors belong to this entity and how these tumors should be treated. In this systematic review with meta-analysis, we analyzed all reports on pediatric patients with malignant rhabdoid liver tumors, but also with so-called small cell undifferentiated liver tumors. This is another rare liver tumor subtype that has recently been regarded to belong to the entity of rhabdoid tumors by some authors. The main result of this study is that these two tumor subtypes show large overlap on several levels and even mixtures of both histological patterns have been documented. Our meta-analysis provides an evidence base for the recommendation to classify these two tumor subtypes as one entity. We showed that treatment of these tumors with hepatoblastoma directed chemotherapy is ineffective and that a therapy with chemotherapy regimens initially applied for soft tissue sarcoma is associated with a significantly better survival. This study represents the highest level of evidence available for these rare liver tumors.

Abstract

Background: Rhabdoid liver tumors in children are rare and have a devastating prognosis. Reliable diagnosis and targeted treatment approaches are urgently needed. Immunohistochemical and genetic studies suggest that tumors formerly classified as small cell undifferentiated hepatoblastoma (SCUD) belong to the entity of malignant rhabdoid tumors of the liver (MRTL), in contrast to hepatoblastomas with focal small cell histology (F-SCHB). This may have relevant implications on therapeutic approaches. However, studies with larger cohorts investigating the clinical relevance of the histological and genetic similarities for patients are lacking. Purpose: To analyze possible similarities and differences in patient characteristics, tumor biology, response to treatment, and clinical course of patients with MRTL, SCUD and F-SCHB. Applied therapeutic regimens and prognostic factors are investigated. Methods: A systematic literature search of MEDLINE, Web of Science, and CENTRAL was performed for this PRISMA-compliant systematic review. All studies of patients with MRTL, SCUD and F-SCHB that provided individual patient data were included. Demographic, histological, and clinical characteristics of the three subgroups were compared. Overall survival (OS) was estimated with the Kaplan–Meier method and prognostic factors investigated in a multivariable Cox regression model. Protocol registered: PROSPERO 2021 CRD42021258760. Results: Fifty-six studies with a total of 118 patients were included. The two subgroups MRTL and SCUD did not differ significantly in baseline patient characteristics. However, heterogenous diagnostic and therapeutic algorithms were applied. Large histological and clinical overlap between SCUD and MRTL could be shown. Two-year OS was 22% for MRTL and 13% for SCUD, while it was significantly better in F-SCHD (86%). Chemotherapeutic regimens for hepatoblastoma proved to be ineffective for both SCUD and MRTL, but successful in F-SCHB. Soft tissue sarcoma chemotherapy was associated with significantly better survival for MRTL and SCUD, but was rarely applied in SCUD. Patients who did not undergo surgical tumor resection had a significantly higher risk of death. Conclusions: While F-SCHB is a subtype of HB, SCUD should be classified and treated as a type of MRTL. Surgical tumor resection in combination with intensive, multi-agent chemotherapy is the only chance for cure of these tumors. Targeted therapies are highly needed to improve prognosis. Currently, aggressive regimens including soft tissue sarcoma chemotherapy, extensive resection, radiotherapy or even liver transplantation are the only option for affected children.

Cytologic features of malignant rhabdoid tumor of the liver: A case report and literature review

As one of the SMARCB1-deficient tumors, malignant rhabdoid tumor (MRT) of the liver is a rare and aggressive malignancy, typically in young children below the age of 3 years. The diagnosis of MRT of the liver is challenging both clinically and pathologically due to the rarity of the tumor and misdiagnosing it as a hepatoblastoma is not uncommon. Although MRT of the liver and hepatoblastoma share some similar clinical and morphological features, their prognosis and the clinical management are significantly different. Therefore, an accurate diagnosis of MRT or hepatoblastoma is critical for patient care. Here we report a case of an 8-month-old female with MRT of the liver diagnosed by fine needle aspiration and core biopsy. The cytologic and histological features, the results of immunohistochemical studies, and clinical follow-up information are presented. Recent literature regarding the diagnosis and treatment of this tumor were reviewed.

Liver biopsy for hepatoblastoma: a single institution's experience

BACKGROUND/PURPOSE

Hepatoblastoma diagnoses require liver biopsies. We aimed to investigate factors affecting the success of liver biopsy for hepatoblastoma diagnoses.

METHODS

Data from patients with hepatoblastoma, including their demographic and clinical data, biopsy procedure information, pathologic diagnoses and subclassification, and surgical complications, were retrospectively reviewed.

RESULTS

Of 153 patients who underwent liver biopsy, 28, 93, and 31 underwent computed tomography-guided, digital subtraction angiography-guided, and ultrasound-guided percutaneous biopsies, respectively, and one underwent a laparoscopic liver biopsy. One patient developed postoperative bleeding requiring a blood transfusion. The median number of specimens collected was 3. One-hundred and forty-four (94.1%) patients' HB diagnoses were confirmed through biopsies, and 96 (62.7%) patients' HB diagnoses were subclassified. Seven surgeons and eight interventional radiologists performed the biopsies. The diagnostic success rate did not correlate with the biopsy technique or the specialist who performed the biopsy. Significantly more specimens were biopsied from the patients whose diagnoses were subclassified (3.34 ± 1.08) than from those whose diagnoses were not subclassified (2.81 ± 0.79). Surgeons tended to collect more specimens than the interventional radiologists.

CONCLUSION

Percutaneous liver biopsy is safe and effective for diagnosing hepatoblastoma, and its complication rate is very low. Collecting >3 pieces of tissue is preferred.

LEVEL OF EVIDENCE

III.

Cytomorphology of hepatoblastoma with histological correlation and role of SALL4 immunocytochemistry in its diagnosis, subtyping, and prognostication

BACKGROUND

Hepatoblastoma (HB) is the most common malignant pediatric liver tumor, and cytology material is often the only tissue available for evaluation before definitive therapy. Subcategorization of HB based on cytomorphological features thus carries an important role in its prognostication. Spalt-like transcription factor 4 (SALL4), a marker of embryonic stem cells that is also found in the fetal liver, is reactivated in certain liver tumors. Limited studies have evaluated its role in HB. This study was aimed at evaluating the cytomorphological features of HB and assessing the utility of SALL4 immunocytochemistry (ICC) in its subtyping and prognostication.

METHODS

Pretherapy fine-needle aspiration smears from patients diagnosed with HB over a period of 9 years were retrieved. Aspirates were subclassified on the basis of the cytomorphology and were correlated with the histology wherever it was available. ICC for SALL4 was performed in 33 cases, and nuclear staining was considered positive.

RESULTS

A total of 53 HB cases were included with 30 available postchemotherapy resection specimens. All the patients were diagnosed as epithelial HB on cytology, and the cases were subclassified as pure fetal (9 of 53), pure embryonal (2 of 53), or combined epithelial HB (42 of 53). There was good concordance between cytology and histology for subtyping. SALL4 immunostaining displayed strong and diffuse nuclear positivity in the embryonal component while focal and weak to negative staining in fetal cells.

CONCLUSIONS

Fine-needle aspiration cytology serves as a rapid and effective tool for a correct diagnosis of HB before the implementation of chemotherapy, and SALL4 may serve as a useful diagnostic and prognostic marker.