Malignant Triton Tumor

Malignant triton tumors are now classified as a variant of MPNSTs. They occur most often in patients with NF1 and consist of neurogenic and rhabdomyoblastic components.[25] Most malignant triton tumors are reported in adults, although they may also arise in children and adolescents.[26]

Distinguishing between malignant triton tumors and NF1-altered rhabdomyosarcomas can be difficult. The genomic characteristics of malignant triton tumors can aid in differentiating between the two tumors. CDKN2A deep deletions and loss-of-function alterations in genes of the PRC2 complex (e.g., SUZ12 and EED1) are commonly observed in malignant triton tumors, while they are uncommon in NF1-altered rhabdomyosarcomas. The loss of PRC2 function leads to loss of H3K27me3 expression, a finding that is common in malignant triton tumors. H3K27me3 expression is generally maintained in rhabdomyosarcomas.[26-28]