Spontaneous Meningoencephalocele of the Temporal Bone

Abstract

To describe the clinical presentation and the radiological and surgical findings in patients with spontaneous meningoencephalocele of the temporal bone. Retrospective case series. Academic, tertiary care medical center. Fifteen consecutive patients with surgically confirmed meningoencephalocele of the mastoid and middle ear, without a history of trauma, tumor, cholesteatoma, or surgery of the mastoid or cranium, who were treated at our institution between January 1, 1999, and December 31, 2006. Ten of the 15 patients were women. Ages ranged from 31 to 77 years, with 12 patients 50 years or older. The most common presenting complaint was new-onset hearing loss in 14 patients, followed by aural fullness and headache. Cerebrospinal fluid formed an effusion in the middle ears of 13 patients and was most commonly identified when myringotomy resulted in continuous clear otorrhea. Four subjects had a history of adult-onset recurrent acute otitis media with intermittent otorrhea, which in 1 case was complicated by brain abscess. At least 1 full-thickness defect of the tegmen associated with cortical thinning of the middle fossa floor was identified in all cases on high-resolution computed tomography. At surgery, herniations of meningeal and cerebral tissue were seen through 1 (7 cases) or 2 (8 cases) defects in the middle fossa floor. Obstruction of antral aeration by the meningoencephalocele was present in all 4 cases associated with otitis media. The onset of otitis media, including middle ear effusions at 40 years or older, warrants the consideration of a meningoencephalocele of the ear. The appearance of tegmental defects and cortical thinning of the middle fossa floor on computed tomography provides a strong indication of the diagnosis and of the need for surgical repair.