Temporal bone cholesterin cyst based on chronic otitis media: A case report

Abstract

We encountered a case of a temporal cyst in a patient with chronic otitis media. The patient was a 65-year-old woman. Her chief complaint was otorrhea and impaired hearing in the right ear. She had been suffering from otitis media of the right ear since childhood. She had visited a medical practitioner in her neighborhood, complaining of increased otorrhea. At this time, a mass was detected in the right auditory canal. She was referred to our hospital for further examination of the mass. The tympanic membrane was not visible because of the mass in the external auditory canal. Pure-tone audiometry showed that she was deaf in the affected ear. A computed tomography scan showed a low-density area extending to the posterior cranial fossa and external auditory canal, obscuring the temporal bone. The mass was punctured, and a dark brown fluid was suctioned out. Cytological examination of this fluid showed the presence of red blood cells, histiocytes, and lymphocytes. Therefore, we suspected the mass to be a cyst of the temporal bone and performed an operation. During the surgery, we found a cyst in the mastoid process, accompanied by a cholesterin granuloma. The tympanic membrane was severely perforated, and an inflammatory granuloma was found extending from the mastoid process to the tympanic isthmus, thus completely obstructing the ventilation route. The cyst was thought to have developed because of the obstruction of the aditus ad antrum. We resected the malleus and incus and then attempted to correct the obstruction.
We did not reconstruct the ossicular chain because the patient was already deaf in the concerned ear. Pathological examination showed the presence of cholesterin in the cyst wall.