Neoplasm of mixed mesenchymal and neuroepithelial origin of the optic nerve.

A case is reported of a 19-year-old male having right proptosis for 4 years because of a mixed meningioma and astrocytoma of the ipsilateral optic nerve. The sheath of this nerve is analogous to the leptomeninges, and neuroglial cells constitute the stroma of the nerve. Both meningioma and astrocytoma therefore can arise primarily in the optic nerve, and they may be combined in the same mass, forming a neoplasm of mixed mesenchymal and neuroepithelial origin.