A Case of Spongiotic Osteoma Arising in the Supratubal Recess

Osteoma of the middle ear is a rare condition in which tumors composed of mature bone grow. In the present study, we experienced a case of an osteoma causing the obstruction of the supratubal recess of the Eustachian tube, resulting in a depression in the pars flaccida of the tympanic membrane and fixation of the ossicles. The patient, a 37-year-old woman, had been aware of hearing loss for two years. Tympanic membrane findings showed a depression in the pars flaccida of the tympanic membrane, and audiometry showed mixed hearing impairment. A temporal bone computed tomography (CT) showed a spherical osteoma in the supratubal recess, with the ear ossicles adhering to the canopy with osteophytes. The patient underwent an endoscopic resection of the osteoma and tympanoplasty, and after two surgeries, her hearing improved. The osteoma in the supratubal recess was found to be a spongiotic osteoma. The osteophyte of the canopy was a compact osteoma. The slowly increasing spongiotic osteoma was thought to have exacerbated the ventilation of the epitympanum, leading to a depression of the pars flaccida of the tympanic membrane and the formation of compact osteoma due to inflammation.