Bilateral osseous stenosis of the internal auditory canal: case report

Osteomas as well as exostoses of the internal auditory canal are rare, benign, usually slow-growing lesions. The most common localizations of these temporal bone lesions are the mastoid cortex and the external auditory canal. A rare case is reported of bilateral osseous stenosis of the internal auditory canal, in the absence of clinical (auditory, vestibular and facial nerve) symptoms. In the absence of auditory, vestibular and/or facial nerve symptoms, long-term follow-up should be assessed; surgical intervention may be warranted only if symptoms are present.     

Ganglioneuroma of the internal auditory canal: a case report

Ganglioneuroma is a rare, benign, slow-growing tumor thought to develop from cells of neural crest origin, even though hypotheses on the pathogenesis of that lesion differ. Ganglioneuromas, which do not release excessive catecholamine or steroid hormones, develop primarily in the posterior mediastinum and retroperitoneum. Because of their slow growth, many ganglioneuromas are large when they are diagnosed. In this case report, a 50-year-old woman with hearing loss is described. Magnetic resonance imaging revealed a mass (3 x 4 mm) in the internal auditory canal (IAC). The encapsulated tumor was entirely excised via the middle fossa approach. The results of histopathological examination indicated that the excised lesion was a ganglioneuroma. To our knowledge, this is the first report of a ganglioneuroma of the IAC. We suggest that ganglioneuroma be considered in the differential diagnosis of all tumors of the IAC.     

Bilateral narrow duplicated internal auditory canal

Internal auditory canal (IAC) anomalies are rare malformations that may include alterations of shape, size or orientation of the IAC. Bilateral duplication of IAC is a very rare malformation and only one case has been described in literature. We report a case of bilateral duplicated IAC together with other inner ear anomalies.     

Bilateral external auditory canal squamous cell carcinoma: a case report

Squamous cell carcinoma (SCC) of the external auditory canal (EAC) is an extremely rare malignant tumor with a prevalance between 1 and 6 cases per 1 million population. The incidence is higher in patients presenting with otological diseases (1 in 5,000 to 15,000). Certain associating factors have been described in the literature. This malignancy frequently presents with symptoms similar to a case of otitis externa or a chronic suppurative otitis media. In this paper, we present a patient who had bilateral SCC of EAC caused by radiotherapy for nasopharyngeal carcinoma. To our knowledge, our case is the fifth bilateral SCC of the EAC and the first bilateral radiotherapy related SCC of the EAC reported in the literature so far.     

Facial nerve neuroma in the geniculate ganglion extending into the internal auditory canal: A case report

Facial nerve schwannoma is a very rare benign tumor representing less than 1% of intrapetrous lesions. Our patient is a forty-one year old female who has suffered from recurrent right facial palsy for the last six years. She was first misdiagnosed as having Bell’s palsy and received corticosteroids which resulted in little improvement. She then had facial nerve decompression surgery which resulted in a partial improvement. Since then, she has suffered from recurrent attacks of facial palsy. Two years ago, she came to our hospital seeking further treatment options. The final diagnosis made by MRI was a possible facial nerve tumor. To obtain a better facial outcome, total tumor removal was performed through the middle cranial fossa approach along with facial-hypoglossal nerve end-to-side anastomosis through transmastoid approach. Her hearing was preserved, and she obtained a better facial outcome than that of her preoperative level. In conclusion, facial nerve schwannoma has the potential to be misdiagnosed as Bell’s palsy which might lead to a delay in diagnosis, and end-to-side neurorrhaphy may be an effective alternative in a selected case.     

Bilateral spontaneous symptomatic temporomandibular joint herniation into the external auditory canal: A case report and literature review

Spontaneous temporomandibular joint (TMJ) herniation is the entity of protrusion of the retrodiscal contents of the TMJ into the external auditory canal (EAC) through a persistent Huschke’s foramen. There have been a number of reports of spontaneous TMJ herniation, but there are no reports of bilateral symptomatic TMJ herniation. We report a case of a 70-year-old man who complained of a crunching sound in both ears during mastication. Examination showed bulging from the anterosuperior wall of the EAC on each side when the patient opened his mouth, which pushed the tympanic membrane medially. Bony defects in the corresponding area were seen on computed tomography. We describe a very rare case of bilateral spontaneous TMJ herniation that caused symptoms by having a direct impact on the tympanic membrane.     

Cavernous hemangioma of the internal auditory canal: a case report and review of the literature

Cavernous hemangiomas are rare lesions that may be difficult to distinguish from acoustic neuromas, schwannomas, or other lesions of the cerebellopontine angle on imaging studies. The clinical history, workup including radiologic evaluation, histologic assessment, and a brief review of the literature are presented.     

Mucoepidermoid carcinoma of the external auditory canal: case report

This study reports a case of mucoepidermoid carcinoma (MEC) of the external auditory canal, which to date has only been described once in literature. Because the lesion is extremely rare, it is particularly difficult to classify it into stages following normal diagnostic parameters. This obviously limits the possibilities of treatment that consequently are either empirical or based on those of squamous cell carcinoma. The problems in the diagnosis and the possible methods of treatment of mucoepidermoid carcinoma are discussed.     

Osteomas of the internal auditory canal: a report of two cases

OBJECTIVES: To determine the optimal medical or surgical treatment of osteomas of the internal auditory canal (IAC) as well as their growth characteristics. STUDY DESIGN: Information was obtained from case histories, images from computed tomography and magnetic resonance imaging, surgical and pathologic findings, and long-term clinical results. METHODS: Two patients, along with 10 additional patients reported in the literature, with osteomas of the IAC with varying symptoms were studied. Clinical history, audiometric and vestibular test results, and radiographic studies were reviewed on all patients. Histopathologic examination of the surgical specimens confirmed the presence of osteomas. The clinical outcomes were studied to determine if the preoperative symptoms had resolved. RESULTS: Eight of 12 patients underwent surgical removal of their IAC osteomas. Three of eight patients had total resolution of all symptoms. Three patients had improvement of their sensorineural hearing loss. Five patients had resolution of their dizziness. Four patients noted resolution of their tinnitus. In the absence of auditory symptoms, vestibular symptoms may be controlled with medical therapy. Long term follow-up of the two patients discussed showed little or no growth over a 4- to 5-year period. CONCLUSIONS: Surgical intervention may be warranted to remove an osteoma of the IAC if symptoms are present. Patients should be made aware that symptoms may or may not improve. Continuation of symptoms may be a result of chronic compression of the auditory and vestibular nerves.     

Patulous internal auditory canal

OBJECTIVE: To investigate a rare anomaly of the internal auditory canal known as a patulous canal and its relationship to hearing impairment. METHODS: High-resolution computed tomographic scans of the temporal bones of patients who presented between August 2001 and August 2002 were reviewed. The patients' medical charts were evaluated for age, sex, and hearing impairment, and the computed tomographic scans were examined for the presence of a patulous canal. RESULTS: The study group included 645 patients who underwent high-resolution computed tomography of the temporal bones for various reasons, including sensorineural hearing loss (50% of patients). A patulous canal without any associated anomaly of the labyrinth was the only finding in 2 patients. Both patients had chronic middle ear disease along with conductive hearing loss. CONCLUSION: Patulous canal is a rare anatomical variant of the internal auditory canal (0.3%), and its association with inflammatory ear disease accompanied by conductive hearing impairment appears to have been incidental in both cases in the present study.     

Meningioma of the internal auditory canal

The great majority of tumors that arise in the internal auditory canal are schwannomas of the eighth cranial nerve (acoustic neuromas). Meningiomas constitute the second largest group of posterior fossa tumors. Meningiomas arise from arachnoid villae, the apparatus responsible for cerebrospinal fluid absorption, in proximity to a major vein or dural sinus in most cases. Arachnoid villae are also present along neural foramena at the base of the skull. They have been observed histologically in the internal auditory canal (IAC), and are the probable site of origin of meningiomas in this location. Larger cerebellopontine angle meningiomas occasionally possess a significant intracanalicular component; however, these lesions usually originate from the meningeal lining of the posterior petrous face adjacent to the sigmoid, superior petrosal, or inferior petrosal sinuses and prolapse into the IAC. Two meningiomas have recently been observed that extensively involved the IAC, one of which arose from the lining of the IAC. The clinical manifestations of these meningiomas mimicked those of acoustic neuromas. Preoperative radiographic studies, including magnetic resonance imaging, were unable to differentiate these from acoustic neuromas. Meningiomas have a higher rate of recurrence than acoustic neuromas and should be excised with surrounding dura and several millimeters of subjacent bone. Meningiomas that extensively involve the IAC have a tendency to invade the inner ear and the deeper portions of the temporal bone. In meningiomas that involve the lateral portion of the IAC, consideration should be given to exenteration of the cochlea and semicircular canals.     

Exostosis of the internal auditory canal

Although exostoses of the external auditory canal are not uncommon, those of the internal canal are extremely rare. One of these is described occurring in a 53-year-old man whose rapidly progressive hearing loss was without any associated abnormality.     

Meningioma of the internal auditory canal

A comprehensive literature search identified only 14 well-documented cases of intracanalicular meningioma. A case is presented of meningioma confined to the internal auditory canal which was excised using a sub-occipital retrosigmoid approach. Preoperative MRI and CT scans were suggestive of intracanalicular vestibular schwannoma. Only the intraoperative findings, which were confirmed by the histological data, revealed that the tumor was a meningioma. We review the literature and discuss the diagnostic and therapeuticissues relating to these tumors.