Localized Thickening Of The Tympanic Membrane (Eardrum)
A healthy 24-year-old female presents for a routine clinic appointment. She has no complaints. She has no history of ear infections or trauma. She has normal hearing. Examination of her right ear with the Wispr Digital Otoscope reveals this image.
What abnormality do you note with the eardrum?
The patient has a localized thickening of her tympanic membrane (eardrum).
This appears as a “bubble” in the middle of the eardrum. You will also note that the cone of light from the otoscope is distorted by the thickening. Dr. Michael Poole has described this as a “fibrous disk” in chapter 5 of his excellent book, “Otitis: The Expert’s Diagnostic Guide.”
The tympanic membrane (eardrum) is comprised of three layers of tissue. The (1) outer cutaneous layer, the (2) middle fibrous layer, and the (3) inner mucosal layer. In the case of this patient, it appears that there is a localized thickening of either the outer cutaneous or middle fibrous layers. The cause of this is not known, but it does not seem to involve either infection or trauma. It is likely of embryologic origin. Multiple exams of this same ear have occurred over several years and the presentation has been stable.
In some cases, the thickening can be quite dramatic, and appearance may be confused with bullous myringitis. The distinction between the two is the complete lack of any symptoms with the layer thickness as opposed to significant distress (pain) and erythema (redness) associated with bullous myringitis. There is no apparent clinical significance associated with this finding. Here is another case featuring a fibrous disk.