This is an uncommon example of mixed-histology rhabdomyosarcoma.
Classic Embryonal - variable myogenin
Dense Emb/Solid Alveolar - strong, diffuse myogenin
Sclerosing - Weak/absent myogenin
Given varied histology and presence of "solid alveolar" vs "dense embryonal" histology, we performed FISH, PCR and array cGH on two separate block.
ALL methods failed to show a FOXO1 fusion.
Thus, this is: fusion-negative ERMS