Clear cell meningioma: a case report.

A case of clear cell meningioma in a 12-year-old male is reported. The tumor was located at the left side cerebellopontine angle, and characterized by sheets of patternless clear cells rich in cytoplasmic glycogen. Vague whorl formation and focal small clusters of typical meningothelial cells were the most important diagnostic features. The tumor cells showed positive immunoreactivity for vimentin, epithelial membrane antigen (EMA), and S100 protein. Cytokeratin and glial fibrillary acidic protein (GFAP) were negative. Ultrastructural features exhibited were abundant cytoplasmic glycogen particles, desmosome-like junctions and tangles of intermediate filaments, while cell membrane interdigitations were few. Clear cell meningioma is rare and is potentially aggressive in that it may recur, spread locally, and even metastasize, despite its bland histologic appearance. There is probably a predilection for younger age group. It is histologically unique but should be differentiated from other mimicking clear cell tumors of the central nervous system, including metastatic renal cell carcinoma, hemangioblastoma, oligodendroglioma, and clear cell ependymoma.