[Immunocytochemical diagnosis of embryonal rhabdomyosarcoma of the orbit]

The authors report on two patients with embryonic rhabdocytosarcoma of the orbit. The tumor in a nine-year-old girl was classified histologically as being of differentiated type and was characterized immunohistochemically by myoglobin. In a two-year-old girl an embryonic rhabdocytosarcoma of a less differentiated (intermediate) type was found which was characterized immunohistochemically by desmine. The differentiated tumor containing myoglobin, in the nine-year-old girl, responded better to chemotherapy. Eighteen months after institution of therapy both patients are healthy and free of recurrences. Immunocytochemical characterization of embryonic rhabdomysarcomas is clinically important, for both diagnosis and prognosis.