Schwannoma de base anterior de cráneo

Utility of Schwann/2E and Sox10 in distinguishing CD57-negative olfactory groove schwannoma from olfactory ensheathing cell tumor: A case report and review of the literature

We herein report a patient who was diagnosed as having olfactory groove schwannoma (OGS) which was negative for CD57 (Leu7) but positive for Schwann/2E and Sox10. A 13-year-old female with a chief complaint of headache was referred to our department due to a tumor lesion in the anterior skull base identified by magnetic resonance imaging (MRI). At the first visit, she did not exhibit altered consciousness, motor palsy, anosmia, seizures, or café au lait spots. On contrast-enhanced computed tomography (CT), a heterogeneously enhanced tumor, 50 × 45 × 50 mm in size, was observed at the anterior skull base. The left cribriform plate was thinner on bone window CT. The tumor exhibited strong, heterogeneous gadolinium enhancement on MRI as well. Slight tumor staining was observed by angiography of the left internal carotid artery but not the left external carotid artery. The patient was preoperatively diagnosed as having meningioma and underwent gross tumor resection via the basal interhemispheric approach. The tumor was strongly positive for S-100 protein and negative for epithelial membrane antigen and CD57 by immunostaining. The tumor was positive for both Schwann/2E and Sox10, which aided in the differential diagnosis between OGSs and olfactory ensheathing cell (OEC) tumors, and the definitive diagnosis was OGS. The assessment of immunoreactivities for Schwann/2E and Sox10 might be necessary to differentiate CD57-negative Schwannomas from OEC tumors.

Olfactory Nerve Schwannoma: A Case Report and Review of the Literature

Schwannomas are benign tumors, which arise from the Schwann cells of the central or peripheral nerves. They form 8% of all intracranial tumors and most of the cases arise from vestibular division of the 8 ^th cranial nerve. Rare cases are shown to arise from the olfactory or optic nerve, being devoid of myelin sheath. Up to date and according to our best of knowledge, 66 cases have been reported till now. Here we present a review of the literature and a case report of a 56-year-old male with an accidently discovered anterior cranial fossa schwannoma, following a road traffic accident. Tumor was completely excised, using a right frontal approach. Histopathology revealed Antoni-A cellular pattern. Although rare, but olfactory nerve schwannomas should be included in the differential diagnosis in anterior cranial fossa space occupying lesions, and the approach should be designed taking into consideration, this rare entity.