Sarcoma arising in oligodendroglioma of the brain

A case is reported of a tumor composed of both oligodendrogliomatous and sarcomatous elements. The interpretation is offered that the sarcoma arose secondarily by neoplastic transformation of the hyperplastic blood vessels formed in response to the presence of the oligodendroglioma. This tumor may be considered analogous to the astrocytoma-sarcoma, which is much more common, and to the metastatic carcinoma with secondary sarcoma, of which one case has been reported.