2016 Volume 26 Issue 5 Pages 674-680
Congenital cholesteatoma of the middle ear can be classified into two types: the closed type is characterized by the development of a keratotic cyst, and the open type is characterized by a wide, flat section of epidermal tissue that forms part of the middle ear mucosa. The closed type can be easily diagnosed by the observation of a white mass through the tympanic membrane (TM). However, the open type is difficult to diagnose otoscopically. In addition, cholesteatoma can develop as a secondary condition. In some cases of secondary cholesteatoma, the epidermis extends into the medial surface of the TM from the margins of a TM perforation because of the inflammation of the tympanic cavity and the lack of retraction of the pars flaccida of the TM. Secondary cholesteatoma tends to affect the aged and is characterized by large TM perforations, epithelial invasion from around the handle of the malleus, long-lasting perforations, and restricted mastoid air cell growth. We encountered three cases of cholesteatoma with unusual characteristics. The cases involved younger individuals, and exhibited marginal small perforations of the TM; moreover, the causes of the TM perforations were unclear, and the patients’ mastoid cells showed good aeration and growth. At first, these patients were diagnosed with otitis media with effusion (OME), acute otitis media (AOM), or calcification of the TM because they had a white TM, which did not appear perforated. We now suspect that these patients had open-type congenital cholesteatoma with TM perforation. Clinicians should be aware that open-type congenital cholesteatoma at the medial surface of the TM can be misdiagnosed as OME, AOM, or calcification of the TM. In cases involving TM perforations, differentiating between open-type congenital cholesteatoma and secondary cholesteatoma is important.
