鼓室乳突腔之異位神經膠組織

Ectopic neuroglial tissues in the head and neck region often involve midline structures, including the nose and nasopharynx. Ectopic neuroglial tissue arising in the tympanomastoid cavity is rare, and we describe one such patient seen in July 2002. Her initial symptoms included a several year history of intermittent left otorrhea and progressive hearing impairment. On examination, a retracted pocket was found over the postero-superior quadrant of the left eardrum. An audiogram identified left-sided moderate conductive hearing loss. Computerized tomography identified a soft tissue mass infiltrating the left mastoid cavity and epitympaneum without bony destruction. An exploratory tympanotomy and mastoidectomy showed the soft tissue mass occupying the left mastoid cavity and surrounding the ossicular chain. Immunohistochemical staining for glial fibrillary acidic protein (GFAP) was positive. Histopathological examination identified ectopic neuroglial tissue. Ectopic neuroglial tissue is a rare cause of middle ear soft tissue masses that should be considered in the differential diagnosis of such lesions.