Extraosseous Ewing's sarcoma. A study of 42 cases.

Fifty patients at the Mayo Clinic (Rochester, MN) from 1935 to 1985 met the histologic criteria for extraosseous Ewing's sarcoma. Forty-two had soft tissue primaries without bony involvement and formed the basis for this retrospective study of the clinical behavior and management of extraosseous Ewing's sarcoma. There were 19 male and 23 female patients (mean age, 22 years). Metastases were documented in 30 of the patients, six at the time of presentation and 24 occurring up to 11 years later, most commonly to lungs or bone. Three patients were lost to follow-up. Sixteen of 35 patients (46%) had local recurrence. Overall survival was 15 of 39 (38.5%) at 5 years. Decreased survival was noted with pelvic tumors, incomplete resections, and presence of metastatic disease, whereas increased survival was associated with wide surgical resection with negative microscopic margins, adjuvant local radiation therapy, and presentation since 1970 (48% 5-year survival compared with 28% before 1970).