Mixed mesenchymal tumors: meningioma and nerve sheath tumor.

Two spinal tumors are reported which consisted of an admixture of meningiomatous and nerve sheath tumor tissues. The former was represented by whorled tissues in both cases, syncytial areas in one and psammoma bodies in the other. The latter was represented by cells with parallel oriented, elongated nuclei and intercellular connective tissue fibers, which contained neurons and myelinated axons. Each of the tumors contained anaplastic areas of increased cellularity and atypism, in addition to the well differentiated areas. On tumor was at cervical levels in a 55 year old man; he has survived for 7 years post-operatively, but with continued pain and motor difficulties. The other was at lumber levels in a 68 year old man; died 6 weeks after operation. No autopsy was obtained. There were no stigmata of von Recklinghausen's disease in either patient. It is suggested that these tumors should not be viewed as teratoid, i.e. of mixed mesenchymal and neurectodermal character. If Schwann cells are considered mesenchymal, as is suggested in other studies, the tumors would represent mixed mesenchymal tumors, like those frequently observed elsewhere, e.g. the angiomyolipomas.