[Ultrastructure of tumors arising from Schwann cells].

Ultrastructural changes have been studied using 67 tumors originated from the Schwann cells. Tumors were induced by means of methylnitrosourea injection with a week intervals. Both benign (fascicular and reticular) and malignant neurinomes were obtained. Main morphological changes were found in the Schwann cells. The tumor cell ultrastructure appeared to be definetely related to the degree of the tumor maturity. The results obtained may suggest that the fine structure of neurogenic tumors is also characteristic of their normal prototype--the Schwann cells.