Abstract
Meningiomas are the most common extra-axial intracranial neoplasm and frequently develop in the parasagittal region. Rarely, meningiomas may involve the middle ear and mastoid, resulting from contiguous spread of adjacent intracranial tumor, or less commonly as an isolated primary tumor of the middle ear. Patients with primary middle ear meningiomas (MEMs) often present with non-specific otologic complaints including hearing loss, otorrhea and otalgia thereby mimicking common chronic otitis media, while secondary lesions more frequently manifest sensorineural hearing loss, cranial neuropathy and other neurologic symptoms from the associated intracranial component. The radiological appearance of MEMs often overlaps with other tumors of the temporal bone. Therefore, a correct diagnosis cannot always be made prior to surgical biopsy. While gross total resection with preservation of existing neurological function is possible with smaller lesions, complete tumor removal may be extremely morbid with more extensive or adherent MEMs. In such cases, aggressive subtotal resection with close radiologic follow-up should be considered. Given the rarity of the studied condition, the literature addressing MEMs is sparse. The current study reviews ten additional cases of MEMs, highlighting the clinicopathologic and radiological features that distinguish meningiomas from other middle ear and mastoid pathology.
1
Introduction
Meningiomas are slow-growing benign tumors and represent the most common extra-axial intracranial neoplasm, accounting for approximately 30% of all adult central nervous system tumors . The incidence of disease increases with age, and there is a predilection for females, particularly between the third to sixth decades of life . It is thought that meningiomas arise from arachnoid cap cells and therefore can occur anywhere where the meninges are found. They most commonly develop near the parasagittal regions, and less frequently involve the olfactory groove, falx cerebri, lateral ventricle, and tentorium cerebelli . Middle ear meningiomas (MEMs) are extremely rare with less than 150 cases reported to date . They can arise primarily within the tympanic space via ectopic arachnoid cells or secondarily through contiguous spread from the jugular foramen, the internal auditory canal (IAC) via transotic invasion, or direct extension through the tegmen tympani or posterior fossa bone plate into the mastoid and middle ear . In this study, we report ten cases of MEMs and discuss the clinicopathologic and radiological features that distinguish meningiomas from other temporal bone pathology.
2
Case reports
Patient 1
A 67-year-old female was found to have an incidental right temporal bone mass after undergoing imaging following head trauma. Surgical intervention was recommended at the time, but the patient declined. She was lost to follow-up, but then presented to clinic six years later with a one-month history of right facial weakness, intermittent facial twitching, and worsening vertigo. Physical examination demonstrated a right House–Brackmann (HB) grade 2 (of 6) facial weakness. Otologic examination revealed external ear canal narrowing with an intact tympanic membrane, but no retrotympanic mass was appreciated. Audiometric testing demonstrated a right profound sensorineural hearing loss. Magnetic resonance imaging (MRI) and computerized tomography (CT) revealed interval growth of the enhancing lytic temporal bone mass from 2.7 cm on initial presentation to 3.6 cm. There was significant erosion of the posterior and middle fossa bone plate, posterior aspect of the IAC and jugular bulb with limited intracranial extension and sparing of the petrous apex ( Fig. 1 ). Following cortical mastoidectomy, the tumor was seen filling the entire mastoid cavity from the antrum to the mastoid tip and involving the sigmoid sinus, posterior fossa dura, and tegmen. The tumor was systematically debulked, and in order to preserve facial nerve function, a thin layer of tumor was left on the facial nerve from the second genu to the stylomastoid foramen. Frozen section biopsy was consistent with meningioma (WHO Grade I) arising from posterior fossa dura. At her most recent follow-up, approximately eight months following surgery, she was found to have HB grade 2 facial nerve function, without evidence of radiologic growth or worsening symptomatology.
Patient 2
A 51-year-old female presented to an outside hospital with a three-year history of intermittent left-sided otalgia and hearing loss. Following her initial evaluation, she underwent a left tympanomastoidectomy at which time a middle ear mass was encountered consistent with encephalocele. The case was subsequently aborted and the patient was referred to our center for further care. Otologic examination revealed a left middle ear mass and audiometry demonstrated a mild conductive hearing loss. CT revealed several areas of tegmen dehiscence and MRI demonstrated a homogenously enhancing middle ear mass with enhancement of the overlying middle fossa dura ( Fig. 2 ). The patient subsequently underwent a tympanomastoidectomy at which time solid tumor was found adherent to the ossicles and tegmen tympani. A middle ear meningioma was confirmed on frozen section pathology. The meningioma was very adherent to the facial nerve and ossicular chain, and given her relative lack of symptoms, subtotal removal was performed. Now more than ten months after surgery, she has not had evidence of growth or worsening symptoms.
Patient 3
A 57-year-old female presented with progressive left-sided hearing loss, tinnitus, and ear fullness. Otologic examination demonstrated a middle ear mass and audiometric analysis revealed a left mild conductive hearing loss. MRI and CT imaging raised suspicion for a MEM ( Fig. 3 ). A transmastoid facial recess approach was used and a mass was encountered filling the majority of the tympanic space with extension into the mastoid antrum. Subtotal resection was performed leaving adherent tumor remnant on the stapes suprastructure. This patient is currently being followed with serial MRI without evidence of growth approximately seven years following treatment.
Patient 4
A 67-year-old female with a history of breast cancer and metastatic carcinoid tumor presented with left-sided hearing loss and recurrent otitis media. Otologic examination revealed a left erythematous tympanic membrane with mild retraction and audiometric testing yielded a left severe mixed hearing loss. CT imaging demonstrated marked hyperostosis of the temporal bone and MRI revealed dural thickening with enhancement, adjacent to opacified mastoid air cells. A tympanomastoidectomy was performed and biopsy was consistent with meningioma. Given her age, comorbidities and lack of significant symptoms, conservative debulking was performed. She has currently been followed for more than nine years without significant tumor growth or change in symptoms.
Patient 5
A 55-year-old female presented with progressive right-sided hearing loss, tinnitus, imbalance, and intermittent dysphagia. On physical examination, a soft-tissue mass was visualized filling the middle ear space, and audiometric testing revealed a right mild-to-profound mixed hearing loss. MRI demonstrated a large extra-axial posterior fossa mass with invasion of the IAC and pars nervosa with extension into the middle ear space ( Fig. 4 ). Based on imaging characteristics, a preliminary diagnosis of meningioma was made. The posterior fossa component was resected via a far lateral approach while tumor involving the temporal bone and jugular foramen was accessed via a transotic approach. Frozen section confirmed a WHO grade I meningioma. The patient has been followed for more than five years following surgery without evidence of residual progressive disease.
Patient 6
A 34-year-old female presented with a history of left-sided otalgia and recurrent otomastoiditis. Otologic examination demonstrated a left retracted tympanic membrane with middle ear effusion, and audiometric testing yielded left moderate conductive hearing loss. Subsequent CT imaging revealed diffuse opacification of the mastoid and middle ear space. An intact-canal wall tympanomastoidectomy was performed for presumed chronic otitis media. At the time of surgery, a middle ear soft tissue mass was encountered which was preliminarily read as granulation tissue on frozen section pathology; however, permanent section revealed a diagnosis of meningioma with surrounding chronic inflammation. After reviewing options, the patient elected to undergo further surgery using a combined mastoid-middle cranial fossa approach. During surgery, meningioma was found enveloping the geniculate ganglion and ossicles. In order to aggressively debulk the tumor, the incus was removed given her existing conductive hearing deficit; however, residual adherent disease was left over the stapes suprastructure and facial nerve to preserve neurological function. Three years following revision surgery she experienced recurrent otitis media and subsequent imaging revealed residual progressive middle ear disease. A subsequent revision surgery was performed with subtotal petrosectomy and external canal overclosure. She is currently more than four years out from her third surgery and has no evidence of tumor regrowth or change in symptoms.
Patient 7
A 60-year-old female presented with a ten-year history of progressive right-sided conductive hearing loss and two years of otalgia. Otologic examination revealed a right erythematous middle ear mass, and a preliminary diagnosis of glomus tympanicum was made. The patient was subsequently taken to the operating room where gross total resection was performed. Given the extensive nature of the tumor, the incus was disarticulated from the stapes, and after tumor resection, ossicular chain reconstruction was performed. Frozen and permanent section pathology revealed the diagnosis of meningioma. Following gross total removal, postoperative imaging confirmed no residual tumor, suggesting that this was indeed a primary middle ear neoplasm arising from congenital ectopic arachnoid. She is currently more than nineteen years from surgery without evidence of recurrence.
Patient 8
A 42-year-old female presented to an outside hospital with a several year history of a firm post-auricular mass and headaches. Based on CT imaging, a preliminary diagnosis of fibrous dysplasia was made and the patient was observed. Over a period of years, the patient experienced worsening headaches, nausea, vomiting and disequilibrium prompting an MRI study of the head. Imaging revealed an extensive, avidly enhancing, mass centered over the left temporal bone with substantial underlying hyperostosis, consistent with an infiltrative temporal bone meningioma. The mass resulted in significant brain compression with resulting edema in the temporal lobe and cerebellum. The patient was subsequently referred to our center for further care. Physical examination revealed a broad, knob-like external deformity involving the post-auricular region. Otoscopy demonstrated a middle ear effusion and audiometry revealed a mild conductive hearing loss with normal word recognition scores. Following transpetrosal access with resection of the intracranial component, a subtotal petrosectomy with ear canal overclosure was performed. The meningioma diffusely involved the mastoid and middle ear cavity resulting in malleus, incus and stapes suprastructure erosion. Gross total resection was achieved, the Eustachian tube was plugged, and the tympanomastoid space was obliterated with abdominal fat. Intraoperative frozen section and final pathology confirmed WHO grade I meningioma. Immediately following surgery, the patient experienced transient dysphagia and mild aphasia, which completely resolved over two weeks. She is currently five months out from surgery with normal facial nerve function and no evidence of tumor recurrence.
Patient 9
A 47-year-old female presented with a one-year history of progressive hearing loss, tinnitus, and otorrhea and was treated with several courses of antibiotics for presumed chronic otitis media. Evaluation at a local medical center confirmed a 30dB conductive hearing loss and a middle ear mass. The patient was subsequently taken to the operating room for exploratory tympanomastoidectomy with biopsy. Extensive disease was encountered along with significant bleeding and a partial canal wall down mastoidectomy was performed. The patient was subsequently referred to our center for further care. Histopathological re-evaluation of the biopsy specimens confirmed the diagnosis of meningioma. Subsequent CT revealed extensive mastoid and middle ear bony erosion without an intracranial component. The patient was then taken to the operative theatre for completion surgery. The mastoid and middle ear were completely filled with tumor and the ossicles eroded. Given the extensive nature of disease and an existing posterior canal wall defect, a modified radical tympanomastoidectomy was performed. Disease was carefully dissected from the Eustachian tube, first genu of the carotid, jugular bulb, and dehiscent tympanic segment of the middle ear. Given the far distance required for travel, she has been followed by her referring physician. The last correspondence received at approximately one year following surgery reported the patient was doing well without evidence of recurrence.
Patient 10
A 54-year-old female was referred for evaluation of a one-year history of left-sided tinnitus, episodic otalgia, and ipsilateral hearing loss. Notably, in 1969, the patient underwent resection of an extensive left posterior fossa meningioma, resulting in ipsilateral lower cranial neuropathy. The patient required reoperation in 1976 for tumor recurrence and ventriculoperitoneal shunt placement. Physical examination revealed a retrotympanic erythematous mass filling the hypotympanum and inferior mesotympanic space that was felt to be consistent with a separate glomus tympanicum or jugulare tumor. Audiometric testing confirmed a mild left-sided conductive hearing loss. Subsequent imaging failed to demonstrate intracranial meningioma recurrence and the patient was taken to the operating room for biopsy. Because of advanced comorbidities and poor surgical candidacy, transcanal biopsy was performed under local anesthesia confirming the diagnosis of meningotheliomatous meningioma. The majority of the middle ear component was removed, but complete resection of hypotympanic disease was not pursued in light of the patient’s poor health status. Given the patient’s history, imaging results, and intraoperative findings, it was presumed that her MEM resulted from residual progressive disease at the jugular foramen. Due to geographic constraints, the patient has been followed by a local neurosurgeon. At last correspondence radiotherapy was entertained, however no further follow-up information is available regarding recurrence or treatment.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
