Clear-cell meningioma of the anterior cranial fossa. Case report and review of the literature.

Clear-cell meningioma (CCM) is a rare subtype of meningioma which occurs at a younger age and has a higher recurrence rate than other subtypes (WHO grade II). CCM usually occur in younger patients and is located in the posterior fossa and spine. The authors report the first case of olfactory groove mixed clear-cell meningioma. A 66-year-old woman was admitted to the SS. Annunziata Hospital (Taranto, Italy) in January 2007 with a two-year history of subtle changes in personality and mental function. On neurologic examination she presented a loss of sense of smell. The magnetic resonance imaging (MRI) showed an olfactory groove meningioma. The computed tomography (CT) and MRI features of CCM are not different from those of common meningiomas. The tumor was totally removed by frontolateral approach on January 24, 2007). Histological examination showed that the tumor was composed of sheet-like uniform and polygonal cells, with abundant clear cytoplasm, and small and bland nuclei. The cytoplasm was heavily laden with granular periodic acid Schiff-positive and diastase-sensitive material representing glycogen. There were no rich vascular networks but scattered collagen bundles within the tumour, little foci areas of necrosis and whorls of meningothelial cells. The neoplastic cells were positive for epithelial membrane antigen (EMA) and vimentin, and negative for glial fibrillary acidic protein (GFAP)? S-100?chromogranin A; Ki-67 labelling showed an index of 1%. The final diagnosis was mixed clear-cell meningioma. Until now only 38 intracranial CCM cases had been reported in English language literature. Different diagnoses for CCM include lesions with clear cell appearance such metastases of renal cell carcinoma and sarcoma, hemangioblastoma, ependymoma, oligodendroglioma, germinoma, chordoma, pleomorphic xanthoastrocytoma, lipid-rich glioblastoma, microcystic and lipomatous meningioma.