A Summary of the Inaugural WHO Classifi cation of Pediatric Tumors: Transitioning from the Optical into the Molecular Era

Pediatric tumors are uncommon, yet are the leading cause of cancer-related death in childhood. Tumor types, molecular characteristics, and pathogenesis are unique, often originating from a single genetic driver event. The specific diagnostic challenges of childhood tumors led to the development of the first World Health Organization (WHO ) Classification of Pediatric Tumors. The classification is rooted in a multilayered approach, incorporating morphology, IHC, and molecular characteristics. The volume is organized according to organ sites and provides a single, state-of-the-art compendium of pediatric tumor types. A special emphasis was placed on blastomas, which variably recapitulate the morphologic maturation of organs from which they originate. Significance: In this review , we briefly summarize the main features and updates of each chapter of the inaugural WHO Classification of Pediatric Tumors, including its rapid transition from a mostly microscopic into a molecularly driven classification systematically taking recent discoveries in pediatric tumor genomics into account.

Automated summary

Pediatric tumors, although uncommon, are the leading cause of cancer-related death in childhood. The development of the first WHO Classification of Pediatric Tumors recognizes the unique characteristics and origin of these tumors, incorporating morphology, IHC, and molecular characteristics. The classification provides a comprehensive understanding of pediatric tumor types, with a special emphasis on blastomas.