Walsh & Hoyt: Extra-Axial Tumors at the Base of the Brain

Extra-axial tumors at the base of the brain produce symptoms primarily through compression and occasionally infiltration of adjacent structures. Basal tumors in the anterior cranial fossa may compress the olfactory nerves and the frontal lobe. Such tumors produce anosmia and symptoms and signs that are indistinguishable from those produced by intrinsic frontal lobe tumors. Similarly, lesions at the base of the brain adjacent to the temporal lobes may produce symptoms and signs identical with those caused by intrinsic tumors of the temporal lobe. Finally, basal tumors in the region of the cavernous sinus, intracranial optic nerves, and optic chiasm produce typical symptoms and signs that include unilateral or bilateral visual loss, ocular motor dysfunction, and ipsilateral trigeminal sensory symptoms.