Extraskeletal ewing's sarcoma: results of combined modality treatment

Abstract

Eleven patients with extraskeletal Ewing's sarcoma (EES) were treated with combined modality therapy at the National Cancer Institute. The diagnosis of EES was reserved for lesions that were identical to Ewing's sarcoma of bone by light and electron microscopy. Diagnostic work-up to rule out a skeletal primary included bone scan, localized views of adjacent bone, and bone tomography. Seven patients presented with an extremity primary and four patients had a truncal primary. No patients had evidence of metastases at presentation. Patients were treated with combined modality therapy consisting of high-dose local irradiation and vincristine, actinomycin D, and cyclophosA SOFT TISSUE TUMOR indistinguishable from Ewing's sarcoma of bone by light microscopy was first described by Tefft et al in five young children, all of whom presented with signs and symptoms of epidural cord compression and a paravertebral soft tissue mass.' Later, Angervall and Enzinger reported a larger series of these soft tissue tumors in adolescents and young adults. 2 In their retrospective series of 39 patients whose pathology was referred to the Armed Forces Institute of Pathology (AFIP) between 1957-1969, there also appeared to be a predilection for these tumors to arise in the paravertebral soft tissues as well as the soft tissues of the lower extremity. The prognosis for these patients was poor, with approximately 75% of the patients dying of metastatic disease to lung or bone, often within one year of diagnosis. However, in these series there was marked variation in the staging and treatment and no analysis of local control. Subsequently, several reports have confirmed the histologic findings by light microscopy of the so-called extraskeletal Ewing's sarcoma (EES).Ž" More recently, electron microscopy has shown that these round cells have no discernible cytoskeleton, intracellular collagen, nor collagenous intercellular matrix," unlike more common soft tissue sarcomas. These findings by electron microscopy help to distinguish EES from primitive or undifferentiated rhabdomyosarcoma, neuroblastoma, and lymphoma. The prognosis for EES patients appears markphamide chemotherapy following a biopsy or local excision. No attempt was made to excise widely the primary tumor mass. Gross tumors generally responded rapidly to the combined modality treatment. Of 11 patients, seven (64%) remain disease free, with a follow-up of three to seven years from completion of therapy. Long-term local control was established in nine of 11 patients (82%). Autopsy findings on two patients with local failure showed no tumor involvement of adjacent bone. Attempts at gross resections by radical surgical procedures do not routinely appear to be necessary in light of the high local control rates with high-dose irradiation.