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

Abstract

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.

SALL4 Oncogenic Function in Cancers: Mechanisms and Therapeutic Relevance

“…Evaluation of SALL4 and LIN28, a type of RNA-binding protein, increased the accuracy of distinguishing classic gastric hepatoid carcinomas (GHCs) from HCCs [144]. SALL4 serves as a diagnostic marker of subtyping of HB for the cytology and the prognostication of patients [145].…”

A Comprehensive Genomic Analysis Constructs miRNA–mRNA Interaction Network in Hepatoblastoma

“…The function of TFs can be either oncogenic or tumor suppressive depending on context (Lambert et al, 2018). Recently, multiple TFs have been demonstrated to modulate the aggressive phenotype and cellular process in HB development (Zhang et al, 2019;Nakra et al, 2020;Wagner et al, 2020).…”

Cytomorphology of paediatric hepatocellular carcinoma: A useful diagnostic adjunct

“…Well-differentiated HCC showed monomorphic tumour cells with regular cell borders and nuclear contours and a maintained nucleocytoplasmic ratio, arranged in trabeculae with a trabecular thickness embryonal type of cells in variable proportions. 19,22,23 In addition, the presence of intracytoplasmic bile is more frequent in HCCs but can rarely be identified in HB even as canalicular bile plugs. 22 Intranuclear cytoplasmic inclusions, though more frequently seen in HCCs, can also be found in HB; thus, their mere presence cannot exclude a diagnosis of HB.…”

“…19,22,23 In addition, the presence of intracytoplasmic bile is more frequent in HCCs but can rarely be identified in HB even as canalicular bile plugs. 22 Intranuclear cytoplasmic inclusions, though more frequently seen in HCCs, can also be found in HB; thus, their mere presence cannot exclude a diagnosis of HB. 22 Intra-cytoplasmic vacuolisation was identified in a case of well-differentiated HCC in the present study and this feature has also been occasionally described in HB.…”