FETAL RHABDOMYOMA: PATHOLOGIC FINDINGS
Marked cellular atypia is absent.
Mitotic figures: rare or absent.
IH findings: Muscle cells positive for myoglobin, desmin, muscle-specific actin.
EM: Organized bundles of thick (myosin) and thin (actin) myofilaments with characteristic banding, intercellular glycogen, small number of mitochondria.