Application of high resolution computer tomography in external ear canal cholesteatoma diagnosis

OBJECTIVE: To evaluate High Resolution Computer Tomography (HRCT) in the diagnosis of external ear canal cholesteatoma. METHODS: In this retrospective study, HRCTs of 27 patients with external ear canal cholesteatoma were reviewed. The changes in the external ear canal, tympanic membrane (TM), scutum, tympanum and mastoid were measured and categorized. RESULTS: Fourteen patients showed no or mild destruction in the external ear canal (stage I group). Eight patients had obvious enlargement in the external ear canal (stage II group) but showed limited destructions of the mastoid bone and no damage of the tympanums. Five patients had serious destruction of the mastoid bone and damage of the tympanum (stage III group). All patients in the stage III group showed a compression of manubriums and TMs, with 3 having damages on ossicular chain. Bone destruction of the vertical section of facial nerve canal was discovered in one case in the stage III group. CONCLUSION: HRCT can provide detail information about the extent of external ear canal cholesteatoma. Such information can be used to identify special situations with serious complications and to differentiate external ear canal cholesteatoma from middle ear cholesteatoma.