Neuromyoblastoma in the rat.

We report three tumours arising in the brain stem or adjacent cranial nerves of the Alderly Park rat. Light microscopy with special stains, immunocytochemistry and electron microscopy supported the conclusion that both neuronal and myoid differentiation occurred in all neoplasms. This was shown by the presence in neural cells of axon-like cell processes and in myoblastic cells of striated myofibrils. Although medulloblastomas occur in man and rats the tumours reported here were not related to the cerebellum. We have termed this tumour neuromyoblastoma.