Morphological studies in malignant tumors of the peripheral nervous system (neurofibrosarcoma, malignant schwannoma, schwann cell sarcoma).

9 cases of malignant tumors of the peripheral nerve sheaths have been observed and their morphology including ultrastructures have been studied. 5 cases could be classified as neurofibrosarcomas, I as a Schwann cell sarcoma. Another cases may be grouped with the melaninproducing Schwann cell sarcomas and 2 cases with the "epitheloid Schwann cell sarcomas". The latter group, their separation or their connection to soft tissue sarcomas and to the "medullo-epitheliomas" of peripheral nerves are discussed.