外耳道に起源をもつ真珠腫病変について

進行例の診療経験からの私見

抄録

There are two possible causes for Cholesteatoma in the external ear canal: Keratosis obturance (KO) and External auditory canal cholesteatoma (EACC). KO is caused by the pressure on embolus, and mainly a transformation of bone at the time of its remodeling. The posterior wall is sustained for long period of time, thus cholesteatoma takes a long time to get into the mastoid. The anterior wall also shows an intense transformation resulting in so-called ballooning. In EACC, inflamation of bone produces destruction, and cholesteatoma goes into mastoid within a short period of time. Therefore, the anterior and inferior walles shows minimal transformation.
Since both EACC and KO develop into a tumor like lesion with essentially the same nature, we call these advanced cases “external auditory canal cholesteatoma”. As for their early stages in the external ear canal, “epidermal keratosis” and “localized cholesteatoma” seem to be clinically appropriate.