RESUMO
The histiocytoses comprise a histopathologically and clinically diverse group of disorders bearing recurrent genomic alterations, commonly involving the BRAF gene and mitogen-activated protein kinase pathway. In the current study, a novel CLTC :: SYK fusion in 3 cases of a histopathologically distinct histiocytic neoplasm arising as solitary soft tissue lesions in children identified by next-generation sequencing and fluorescence in situ hybridization is described. Morphologically, all 3 neoplasms were composed of sheets of cells with round-oval nuclei and vacuolated eosinophilic cytoplasm but, in contrast to classic juvenile xanthogranuloma (JXG), Touton giant cells were absent. A separate cohort of classic JXG cases subsequently profiled by fluorescence in situ hybridization were negative for the presence of a CLTC::SYK fusion suggesting that CLTC::SYK fusion-positive histiocytoma is genetically and histologically distinct from JXG. We postulate that the CLTC::SYK fusion leads to aberrant activation of the SYK kinase, which is involved in variable pathways, including mitogen-activated protein kinase. The identification of a novel CLTC::SYK fusion may pave the way for the development of targeted therapeutic options for aggressive disease.
Assuntos
Histiocitoma , Xantogranuloma Juvenil , Criança , Humanos , Hibridização in Situ Fluorescente , Xantogranuloma Juvenil/genética , Xantogranuloma Juvenil/metabolismo , Xantogranuloma Juvenil/patologia , Proteínas Quinases Ativadas por Mitógeno/genética , Quinase Syk/genética , Cadeias Pesadas de Clatrina/genéticaRESUMO
Vaginal tumors in children are uncommon. This report describes the rare case of an atypical smooth muscle tumor arising from the vagina in a pediatric patient managed with tumor resection, vaginal reconstruction, and continent urinary diversion. We also discuss a review of the literature and a brief report detailing our experience with pediatric vaginal tumors.