Expansile bone cyst and cholesteatoma of the temporal bone.

Objective: To identify primary bony cysts of the temporal bone.

Patient: A single case of a woman presenting with unilateral bulging of the temporoparietal cranium, progressive stenosis of the external auditory canal, and maximal conductive hearing loss.

Intervention(s): Plain x-rays, magnetic resonance imaging, contrast-enhanced computed tomography, audiogram, and modified radical mastoidectomy.

Main Outcome Measure(s): Radiologic and histopathologic diagnosis of a primary bone cyst of the temporal bone obstructing the external auditory canal with a retained cholesteatoma of the middle ear.

Results: Identification of an inflammatory bony cyst of the temporal bone with a retained cholesteatoma of the middle ear resulting in stenosis of the external auditory canal and maximal conductive hearing loss.

Conclusion: Primary bone cyst of the temporal bone can lead to external auditory canal stenosis, middle ear cholesteatoma, and conductive hearing loss.