Pathology: embryonal rhabdomyosarcoma
Rhabdomyosarcoma, embryonal
Adolescent; paratesticular
Sheets of polygonal-spindle cells
Scant amphophilic cytoplasm
Round-ovoid nuclei with mild pleomorphism; conspicuous mitotic activity
Rare epithelioid-rhabdoid cells with abundant eosinophilic cytoplasm; eccentric nuclei
RNA-seq: negative for FOXO1-rearrangement
Rhabdomyosarcoma, embryonal
Loose fascicles of spindle-epithelioid cells; condensation below epithelial structures ("botryoides")
Bright eosinophilic cytoplasm with long tapering processes; conspicuous "cross-striations"
Peripheral nuclei with mild atypia, prominent nucleoli, and occasional multinucleation; occasional mitotic activity
Scattered round-polygonal cells with scant cytoplasm; round nuclei with mild pleomorphism
RNA-seq: negative for FOXO1-rearrangement
Rhabdomyosarcoma, embryonal
Adolescent; paratesticular
Loose fascicles of spindle cell
Eosinophilic cytoplasm with long tapering processes; occasional "cross-striations"
Round-ovoid nuclei with mild-moderate pleomorphism; conspicuous mitotic activity
Scattered epithelioid cells with abundant eosinophilic cytoplasm; eccentric nuclei
IHC: desmin, myogenin, MDM2
RNA-seq: negative for FOXO1-rearrangement
Rhabdomyosarcoma, embryonal
Adolescent; paratesticular
Sheets of spindle-epithelioid cell
Amphophilic cytoplasm with occasional delicate tapering processes
Round-ovoid nuclei with moderate pleomorphism; conspicuous mitotic activity
Focal myxoid stroma; necrosis
RNA-seq: negative for FOXO1-rearrangement