Clinical features
Pleomorphic rhabdomyosarcoma occurs almost exclusively in the deep soft tissues of the lower limbs. There is a peak incidence in the sixth decade.
Immunohistochemistry
Positivity for myogenin is proof of rhabdomyoblastic differentiation.
Differential diagnosis
In children, embryonal rhabdomyosarcoma with anaplastic features
Pleomorphic leiomyosarcoma: more often positive for h-caldesmon
Prognosis
These are highly aggressive sarcomas, with 90-100% of patient showing metastases within five years.