Towards an international pediatric liver tumor consensus classification: proceedings of the Los Angeles COG liver tumors symposium

Abstract

Liver tumors are rare in children, and their diagnoses may be challenging particularly because of the lack of a current consensus classification system. Systematic central histopathological review of these tumors performed as part of the pediatric collaborative therapeutic protocols has allowed the identification of histologic subtypes with distinct clinical associations. As a result, histopathology has been incorporated within the Children's Oncology Group (COG) protocols, and only in the United States, as a risk-stratification parameter and for patient management. Therefore, the COG Liver Tumor Committee sponsored an International Pathology Symposium in March 2011 to discuss the histopathology and classification of pediatric liver tumors, and hepatoblastoma in particular, and work towards an International Pediatric Liver Tumors Consensus Classification that would be required for international collaborative projects. Twenty-two pathologists and experts in pediatric liver tumors, including those serving as central reviewers for the COG, European Socié té Internationale d'Oncologie Pé diatrique, Gesellschaft fü r Pä diatrische Onkologie und Hä matologie, and Japanese Study Group for Pediatric Liver Tumors protocols, as well as pediatric oncologists and surgeons specialized in this field, reviewed more than 50 pediatric liver tumor cases and discussed classic and newly reported entities, as well as criteria for their classification. This symposium represented the first collaborative step to develop a classification that may lead to a common treatment-stratification system incorporating tumor histopathology. A standardized, clinically meaningful classification will also be necessary to allow the integration of new biological parameters and to move towards clinical algorithms based on patient characteristics and tumor genetics, which should improve future patient management and outcome.

MicroRNA therapy inhibits hepatoblastoma growth in vivo by targeting β‐catenin and Wnt signaling

“…HBL differs from HCC by its histologic appearance and development on a liver lacking any underlying chronic disease 1. HBL is classified into several histologic subtypes that recapitulate the different stages of liver development 2, 3. Chemotherapy associated with tumor resection or liver transplantation is the cornerstone of HBL treatment, resulting in a 5‐year patient survival of over 80% 1, 4.…”

Liver cancer biopsy – back to the future?!

“…An international group of experts on pediatric liver tumors has recently called for mandatory liver biopsies in all pediatric patients with liver tumors. 8 We do not believe all adults with liver tumors need biopsies, but developing clinical and trial protocols in adults with HCC that support the important role of biopsies will improve diagnosis of HCC and increase our chance to provide better patient care in the future. O ne of the more active debates in the liver cancer community is whether it is acceptable to base the diagnosis of hepatocellular carcinoma (HCC) on the results of imaging techniques alone or whether biopsy is required.…”

“…[1][2][3][4] Other scientific associations and groups have proposed similar guidelines or have endorsed the AASLD guidelines. [6][7][8][9][10][11][12][13] Biopsy has a place in this algorithm, but only in cases where radiology is not diagnostic. Imaging diagnosis is feasible, but there is a very well-defined set of requirements: The imaging diagnosis is only feasible in a population at high risk for this malignancy (namely, patients with cirrhosis or longlasting liver disease 6,7,11 ) because of the high pretest probability that any detected nodule larger than 10 mm in an at-risk patient is an HCC.…”

Hepatoblastoma Etiopathogenesis

“…HB cases differ in the type and proportion of these components, showing differences in gene expression profiles, patient prognosis and response to therapy [8]. Both, the pure fetal histology in the surgical specimen and the presence of small cell undifferentiated component (SCU) have been proposed as prognostic factors [4,6]. Interestingly, based on gene expression profiling two prognosis subtypes of HB (C1 and C2) with different pathological, clinical and molecular characteristics have been identified [9].…”

“…A third type of primary liver cancer that appears at the late childhood and adolescence was initially called transitional liver cell tumor (TLCT), because it has a mixture of histological patterns characteristic of HB and HCC [3]. This cancer has been recently classified in a new provisional category named hepatocellular neoplasm not otherwise specified [4], awaiting for a better characterization, in an international symposium aiming to develop a consensus classification system for pediatric liver malignancies.…”