外耳道狭窄により診断が遅れた先天性真珠腫例

抄録

A 77-year-old man presented to our hospital with bilateral hearing loss and bilateral ear canal stenosis. We considered that his ear canals had gradually narrowed due to medial meatal fibrosis caused by chronic otitis media, since he had a history of habitual ear scratching in both ears. Computed tomography revealed external auditory canal stenosis on both sides. The tympanic cavity was filled with soft tissue, with destruction of the ossicles, in the left ear. On the basis of these findings, we assumed that the destruction of the ossicles in the left ear was caused by external auditory canal cholesteatoma developing as a result of the stenosis. Exploratory tympanotomy showed that the left middle ear was filled with a cholesteatoma, with erosion of the ossicles. The cholesteatoma was located inside the tympanic membrane without any connection, suggesting that it was congenital. Thus, in this patient, the congenital cholesteatoma had remained undetected until the age of 77. That is because the tympanic membrane could not be observed due to stenosis of the external auditory canal, and even his hearing loss had been diagnosed as mixed hearing loss due to both aging and the stenosis of the external auditory canal, without examination by computed tomography. In patients where it is difficult to observe the tympanic membrane because of ear canal stenosis, it is important to perform imaging to check for internal lesions.