Nerve Sheath Myxoma Involving the Oropharynx; A Case Report

抄録

A rare case of nerve sheath myxoma of the oropharynx in a 54-year-old-woman is reported. Her complaint was slight pain upon swallowing. At the left arcus palatoglossus, a flat, edematous, ulcerated tumor was found and excised surgically. The tumor was well encapsulated, measuring ca. 1.5-1-1cm. The cut surface was yellowish and gelatinous. Histopathologically it consisted of distinct lobules surrounded by fibrous septa. Each lobule was composed of spindle-shaped cells with elongated nuclei surrounded by a myxoid matrix, which stained prominently with Alcian blue. Immunohistochemically the tumor cells stained specifically positive for S-100 protein, neuronspecific enolase, and vimentin. They stained negative for myoglobin, and Factor XIIIa. The staining pattern suggested a neoplasm arising from neuroectodermal cells in the endoneurium of the peripheral nerve. The tumor was diagnosed as nerve sheath myxoma, which is considered to be a specific clinicopathological entity. After three years there has been no recurrence.
Myxomatous tumors in the oropharyngeal region, require a differential diagnosis among nerve sheath myxoma, odontogenic myxoma, soft tissue myxoma, neuroma and schwannoma. They can usually be differentiated easily by histological and immunohistochemical studies. Nerve sheath myxomas are rare; only eight cases in the oral and oropharynx region have been reported in Europe and America and only one case in Japan.