Primary meningeal extraosseous Ewing's sarcoma: case report.

A 25-year-old man presented with a suspected right-sided subdural hematoma after a skiing accident. A large hemorrhagic mass was found and was evacuated. Histological studies demonstrated a highly cellular neoplasm with extensive hemorrhage. Further histological, immunohistochemical (including staining for Ewing's sarcoma cell surface antigen), and ultrastructural analyses of the tumor were consistent with Ewing's sarcoma. Search for other foci of this neoplasm by bone scan, full body computed tomographic scans, magnetic resonance imaging scans of the spine, and a bone marrow aspiration with biopsy failed to detect any soft tissue or bony involvement outside the cranium. This case appears to represent the first report of a primary extraosseous Ewing's sarcoma occupying the cranial subdural area.