Meningeal mesenchymal chondrosarcoma: report of 8 cases with review of the literature.

This paper reviews 8 personally examined cases of primary meningeal mesenchymal chondrosarcoma and 4 similar cases previously reported by others. The clinicopathologic features of these extraosseous intracranial and intraspinal examples are similar to those of other extraskeletal mesenchymal chondrosarcomas. The tumor occurred most often in the second and third decades, showed a moderate tendency to local recurrence (5 of 12 cases) and occasionally metastasized to the lungs (1 case). Both intracranial and intraspinal tumors occurred with equal frequency, but the former, probably due to the later onset of symptoms, had the worse prognosis. Microscopically, they are composed of primitive undifferentiated mesenchymal cells and frequently well-defined islands of hyaline cartilage. There is an apparent correlation between the frequency of mitotic figures and the likelihood of recurrence and metastasis. Electron microscopic study of one example revealed morphologic features similar to those previously described by others and supports the conclusion that the neoplastic cells represent primitive precartilaginous mesenchyme displaying focal cartilaginous differentiation.