[Ultrastructural characteristics of soft tissue rhabdomyosarcomas].

Seven rhabdomyosarcomas of human soft tissues were studied electron microscopically. Certain ultrastructural features characteristic of tumour rhabdomyoblasts were revealed: atypical fibrillar apparatus, spatially uneven process of myofibrillogenesis, disturbed cyto- and histotypical differentiation ratio and others. These features may be used for electron microscopic diagnosis of rhabdomyosarcomas among soft tissue tumours of low differentiation.