![]() Exostoses of the external auditory canal with severe stenosis (Grade III). Table 3.1 Grading of external auditory canal stenosisĪll four quadrants of the pars tensa are perfectly visible.įig. Histologically, it can be differentiated from exostosis by the absence of the laminated growth pattern.Īccording to the extent of both diseases, we developed a classification for EAC stenosis, which is based mainly on the amount of tympanic membrane otoscopically visible ( ▶ Table 3.1 ▶ Fig. Osteoma is a true benign neoplasm of the bone of the EAC, usually unilateral and pedunculated. Other structures at risk are the tympanic membrane and ossicular chain medially, the temporomandibular joint anteriorly, and the third segment of the facial nerve posteroinferiorly. In some cases, surgery is technically difficult and special care is taken to preserve the skin of the EAC. In such cases, and in cases in which a hearing aid is to be fitted, surgical removal of exostoses is indicated. Large lesions, however, can occlude the EAC and lead to conductive hearing loss or retention of wax and debris with subsequent otitis externa. When exostoses are small, they are asymptomatic. It is postulated that the periosteum stimulates an osteogenic reaction with each exposure to cold water, causing this stratification. Histologically, they are formed from parallel layers of newly formed bone. This explains the high incidence of exostoses among divers and cold-water bathers. ![]() The condition is caused by periostitis secondary to exposure to cold water. They vary in shape, being either round, ovoid, or oblong. They are usually multiple, bilateral, and are commonly sessile. Further radiological examinations (CT and MRI scans) are indicated in the suspect of a tumor.Įxostosis are defined as new bony growths in the osseous portion of the external auditory canal (EAC). For example, in case of exostosis and osteomas occluding the EAC a canalplasty is indicated, as well as a surgical treatment is the mainstay for most of the benign and malign tumors involving the EAC. Analysis of patient clinical history and symptoms are also of utmost importance to decide the proper therapeutic management, which is different depending on the pathology. Otoscopy is fundamental for the recognition of each clinical condition. Pathologies affecting the external auditory canal (EAC) are a wide spectrum of diseases that include: bony neoformations of the EAC (exostosis and osteomas), inflammatory diseases (external otitis, otomycosis, and inflammatory stenosis of the EAC), cholesteatoma of the EAC, benign tumors of the ear and skull base extending to the EAC (carcinoid tumor, meningiomas, facial nerve tumors, etc.), temporal bone fractures, and carcinoma of the EAC.
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