sclerosing rhabdomyosarcoma sclerosing rhabdomyosarcoma sclerosing rhabdomyosarcoma is a rare subtype of rhabdomyosarcoma that was characterized by folpe et al. in 2002. it is microscopically characterized by primitive round cells forming microalveoli, nests, and cords in a sclerotic background. sclerosing rhabdomyosarcomaspecialtyoncology