EXTRACRANIAL MENINGIOMA IN THE PARAPHARYNGEAL SPACE

A case of extracranial meningioma in the parapharyngeal space is repor ted. A 24 year old woman presented with swelling and tenderness of the parapharyngeal region. A tumor was palpable in this region, and the t umor was surgically removed. Macroscopically the tumor occurred from t he portion between the axis and atlas. Histologically the tumor cells, which had oval nuclei and a slightly eosinophilic cytoplasm, prolifer ated in fibrous connective tissues to form small nests. As the cell bo rders were not clear, the tumor structure appeared to be syncytium-lik e. Immunohistochemically the tumor cells were positive for anti-viment in antibodies, anti-S-100 protein antibodies and anti-epithelial membr ane antigen (EMA) antibodies in part. Electron microscopically the tum or cells had complex interdigitations of their adjacent plasma membran es. These were studded with many desmosomes. Bundles of intermediate f ilaments were visible in the cytoplasm. On the basis of the clinical, histological, immunohistochemical and electron microscopical features, the tumor was diagnosed as extracranial meningotheliomatous meningiom a. The parapharyngeal space is an extremely rare location for extracra nial meningioma, and our case is the first in Japan as far as we know.