EVIDENCE OF MENINGIOMA INFILTRATION INTO CRANIAL NERVES - CLINICAL IMPLICATIONS FOR CAVERNOUS SINUS MENINGIOMAS

Anatomical and biological studies of cavernous sinus meningiomas help us understand the biological heterogeneity of these tumors. The questi on of whether cavernous sinus meningiomas infiltrate cranial nerves is clinically important because of the effect on treatment planning. In the authors' experience of treating 36 patients with cavernous sinus m eningiomas, tumor invasion into a cranial nerve was documented in two patients in whom a cranial nerve was resected during the cavernous sin us dissection. In both patients, histological examination using hemato xylin and eosin and bodian stains showed infiltration of the cranial n erves by a benign meningioma which, to the best of the authors' knowle dge, is a condition previously unreported. This histological finding o f meningioma invasion into a cranial nerve demonstrates the biological heterogeneity of cavemous sinus meningiomas and raises concern about the invasive character of meningioma. Because not all tumor cells can be identified radiologically or by direct visualization at surgery, oc cult tumor infiltration predisposes a patient to recurrence despite th e best neurosurgical efforts. Evidence of cranial nerve infiltration b y meningioma suggests that, in some circumstances, cavernous sinus dis section in the hope of total removal of a meningioma may be futile and , in the long term, may provide no advantage over treatment options wi th lower morbidity.