open 型先天性真珠腫の3例 Open-type congenital cholesteatoma : A report of three cases
Congenital cholesteatoma is classified into the closed type (characterized by cystic epithelium) and the open type (characterized by membranous epithelium). It has been reported that the closed type is common, while the open type is relatively rare. Since conductive hearing impairment is a presenting symptom in most of the patients with an open type of congenital cholesteatoma, this condition is often detected during exploratory tympanotomy. Although open type cholesteatoma is said to be associated with a high incidence of auditory ossicular malformations, there is still controversy on this issue. We treated 3 patients with the open type of cholesteatoma. The present report described their clinical findings and discussed the characteristics of this disease.<BR>Case 1<BR>A 7-year-old girl with left-sided conductive hearing impairment was referred to our clinic for detailed examination. Since CT scans revealed a defect of the incudo-stapedial joint, exploratory tympanotomy was performed. As a result, a very small open-type cholesteatoma was found, which extended from the region corresponding to the long process of the incus to the facial nerve canal. After dissecting the cholesteatoma, conductive hearing was restored by tympanoplasty (III-i). The patient has had no recurrence 10 years after surgery.<BR>Case 2<BR>A 34-year-old woman presented to her local clinic with left-sided tinnitus. She was referred to our clinic because left-sided conductive hearing impairment was detected, although the tympanic membrane was normal. Since CT scans revealed a defect in the long process of the incus and a slight soft tissue shadow around the defect, exploratory tympanotomy was performed. This revealed an open-type cholesteatoma spreading from the facial nerve canal to the foot plate of the stapes. After resection of the cholesteatoma, conductive hearing was restored by tympanoplasty (IV-i).<BR>Case 3<BR>A 6-year-old boy was referred to our clinic after hearing impairment was detected at a school medical check-up. CT scans revealed a defect in the process of the incus, so exploratory tympanotomy was performed. Membranous tissue was detected near the incudo-stapedial joint, and the head of the stapes was adherent to this tissue. After the membranous tissue was removed, an open type cholesteatoma was found on the facial nerve canal. There were absence of curura of the stapes. His conductive hearing was restored by tympanoplasty (IV-i).<BR>The tympanic membrane is normal in most patients with the open type cholesteatoma, and it is difficult to make an accurate diagnosis of this disease preoperatively based on imaging alone. When patients with conductive hearing impairment and a normal tympanic membrane are seen, it is important to take this type cholesteatoma into consideration along with auditory ossicular malformations and otosclerosis.
- Otology Japan
Otology Japan 17(5), 658-664, 2007-12-25
THE JAPAN OTOLOGICAL SOCIETY