[Pediatric renal cell carcinoma]

Area of Science:

• Pediatric oncology
• Nephrology
• Cancer genetics

Context:

• Renal cell carcinoma (RCC) in children and adolescents is rare, accounting for ~1% of pediatric renal tumors.
• The 2004 World Health Organization (WHO) classification introduced new renal tumor entities specific to young patients.
• Recent advancements have expanded the understanding of rare pediatric RCC subtypes.

Purpose:

• To review and incorporate newly described renal tumor entities into the 2004 WHO classification for pediatric and adolescent patients.
• To detail the characteristics of specific rare RCC subtypes, including those associated with neuroblastoma and TFE3-translocations.
• To highlight the ongoing challenges in classifying a phenotypically diverse group of pediatric renal tumors.

Summary:

• Renal cell carcinoma (RCC) in pediatric and adolescent populations is uncommon, with specific subtypes emerging since the 1997 WHO classification.
• RCC associated with neuroblastoma, occurring years post-diagnosis, often exhibits allelic imbalances on chromosomes 20q13, 2p31-32.2, 13q22, and 14q31.
• TFE3-translocation carcinomas constitute ~20% of pediatric RCCs, characterized by TFE3 protein overexpression due to translocations like t(X;17) and t(X;1), and typically display clear cytoplasm and papillary architecture.
• A significant portion of pediatric RCCs remain unclassified, representing a heterogeneous group with potential for new subtype identification.

Impact:

• Provides an updated classification framework for rare pediatric renal cell carcinomas.
• Enhances diagnostic accuracy for specific entities like TFE3-translocation RCC and neuroblastoma-associated RCC.
• Underscores the need for continued research into the classification and understanding of heterogeneous pediatric renal tumors.