Malignant tumors of nerve sheath origin.

A clinicopathologic study of malignant nerve sheath tumors diagnosed between 1962 and 1979 at the Massachusetts General Hospital was undertaken. During this 17-year period, 24 patients with such a neoplasm were seen while 607 patients were treated for schwannoma or neurofibroma. Criteria were developed for establishing the nerve sheath origin and malignancy of a given neoplasm which allowed a secure diagnosis of malignant nerve sheath tumor to be made in 11 of the 24 cases. In 7 of the remaining cases, the malignant tumors were of uncertain histogenesis and in 6 cases, a new diagnosis was made. The malignant tumors constituted 2% of all neoplasms of the nerve sheath origin diagnosed during this period. An attempt was made to grade these neoplasms, but clinical and histologic parameters were only approximately predictive of their behavior. The treatment and survival or the 11 patients with malignant nerve sheath tumors and the 7 with malignant neoplasms of uncertain histogenesis are detailed and compared. In the former group, 4 patients died within four and a half years and there were eight recurrences in 4 patients. In the latter group, 4 died within three and a half years and there were five recurrences in 3 patients.