Histopathological and Molecular Characteristics of Pediatric Adrenocortical Tumors: where Do we Stand?

Abstract

Pediatric adrenal cortical carcinoma (ACC) is a rare heterogeneous cancer type that is incompletely understood and differs from its adult counterpart in clinical presentation, histopathological characteristics, genomic landscape, and prognosis. Pediatric ACC has a bimodal age distribution for children with ACC, with the highest incidence in young children and adolescents. Tumors commonly present with an endocrine syndrome such as virilization or Cushing’s syndrome, associated with hormone overproduction. Surgical resection is the primary treatment. Adjuvant therapies such as mitotane or chemotherapy can lead to (severe) side effects in children and should be closely monitored. Histopathological assessment commonly relies on the AFIP/Wieneke classification, with the modified reticulin algorithm also providing predictive value. Recently, the two-step scoring system by Picard aimed to integrate the AFIP/Wieneke classification and the Children’s Oncology Group (COG) staging system into a two-step model. Molecularly, pediatric ACC is strongly associated with germline variants of TP53 and loss of heterozygosity of chromosomes 11 and 17. Somatic variants in several genes, including ATRX and CTNNB1, have been identified and are associated with poor prognosis. Multiple factors, such as age, tumor size, and biomarkers, with Ki67-labeling index being most important, are of prognostic value. Despite research advances, overall survival remains poor and worsens with older age at diagnosis and advanced disease. To improve survival rates of pediatric ACC further research is necessary aiming at optimizing therapeutic strategies in these patients. This review summarizes current knowledge of this challenging tumor and highlights recent advances in the field.