Gliosarcoma with direct involvement of the oculomotor nerve: Case report and literature review.

Gliosarcoma is a rare malignant brain tumor, characterized by a biphasic tissue pattern with alternating areas displaying glial and mesenchymal differentiation. We first report a case of temporo-mesial gliosarcoma, extended to the crural and ambient cisterns, with direct involvement of the ipsilateral third cranial nerve and encasement of anterior choroidal, posterior communicant and posterior cerebral arteries, presenting without symptoms of peripheral neuropathy. A 61-year-old woman with 1-month history of intense bilateral frontal-temporal headache resistant to pharmacological therapy and paresis of the left lower midface underwent surgical resection, through pterional trans-sylvian approach, of a right temporo-mesial gliosarcoma which directly involved the ipsilateral oculomotor nerve. Reported cases of gliomas with direct involvement of a cranial nerve, from the third to the twelfth, are very rare, whit no cases of gliosarcoma described. Because of its rarity, sometimes this entity is not considered as diagnostic hypothesis and is misdiagnosed, both during preoperative diagnostic evaluation and during the surgery. Gliosarcoma is a strong challenge for neurosurgeons and neurooncologists because of low incidence, poor prognosis and limited reported cases on literature. This case shows unique features for localization, pattern of growth and clinical presentation.