Sheets and vague nests of round cells
Scant pale eosinophilic cytoplasm
Round euchromatic nuclei with inconspicuous nucleoli; conspicuous mitotic activity
Fibrovascular septa with central loss of cellular cohesion resulting in an "alveolar-like" pattern
IHC: desmin, myogenin
RNA-seq: PAX3::FOXO1
Sheets and nests of round cells
Scant eosinophilic cytoplasm
Round hyperchromatic nuclei with mild pleomorphism; conspicuous mitotic activity
Thin fibrovascular septa separate nests of cells; centrally there is necrosis yielding an "alveolar-like" pattern
IHC: myogenin
RNA-seq: PAX3::FOXO1
Sheets of discoherent round cells
Scant eosinophilic cytoplasm
Eccentric round-reniform nuclei with mild pleomorphism; conspicuous mitotic activity
IHC: desmin, myogenin
RNA-seq: PAX3::FOXO1