Congenital cholesteatoma isolated to the mastoid presenting as stricture of the external auditory canal.

Congenital cholesteatoma may originate at various sites in the temporal bone. Congenital cholesteatoma of the mastoid origin shows a variable clinical presentation, although the least common site is the mastoid process. We report an extremely rare case of congenital cholesteatoma isolated to the mastoid presenting as stricture of the external auditory canal. A 10-year-old boy presented with stricture of the left-sided external auditory canal caused by bulging of the posterior wall of the external auditory canal. Computed tomography showed destruction of the posterior wall of the external auditory canal by a lesion of soft tissue density in the left mastoid cells. At surgery, cholesteatoma was observed in the mastoid cavity. Although destruction of the posterior wall of the external auditory canal was identified, the external auditory canal skin and tympanic membrane were intact, and the aditus ad antrum mucosa was normal. Congenital cholesteatoma isolated to the mastoid was diagnosed. Diagnosis of congenital cholesteatoma isolated to the mastoid should be based on clinical examination, radiological evaluation, and surgical findings. In addition, the possibility of congenital cholesteatoma isolated to the mastoid should be considered in patients with stricture of the external auditory canal.