[Pediatric renal cell carcinoma].

Renal cell carcinoma in children and adolescents is rare and comprises only about 1% of renal tumors in this age group. Since the last WHO classification in 1997, new entities of renal tumors in young patients have been described and have been included into the new 2004 WHO renal cell carcinoma classification. Renal cell carcinoma associated with neuroblastoma comprises 2.5% of renal cell carcinoma in young patients. It occurs several years after neuroblastoma. A large proportion of these tumors show allelic imbalance of chromosomes 20q13, 2p31-32.2, 13q22 and 14q31. TFE3-translocation carcinomas correspond to approximately 20% of renal cell carcinomas in the pediatric and adolescent age group. Both translocations t(X;17)(p11.2;q25) and t(X;1)(p11.2;q21.2) result in immunohistochemically detectable TFE3 protein overexpression. By conventional morphology, TFE3-translocation carcinomas typically show prominent "voluminous" clear cytoplasm and partially papillary architecture. Even according to the revised 2004 WHO classification, in children and adolescents, far more renal cell carcinomas than in the adult age group are currently not classifiable but constitute a phenotypically heterogeneous group with ample potential for future renal cell carcinoma subtypes.