[Imaging diagnosis of benign lesions of the external auditory canal]

Benign lesions of the external auditory canal (EAC) are an infrequent cause of temporal bone CT scan requests. We are not usually well versed in the different pathologies located in the EAC, perhaps because it is "only" a conduit and the relevant anatomical structures are located in the middle and inner ear. Our objective was to improve knowledge of this structure by reviewing the different benign conditions found in this location.

We reviewed the CT studies from 2 years (January 2010 through January 2012), selecting those containing lesions in the EAC. To complement this, due to the importance of these lesions, these medical histories were then analysed considering the presentation and otoscopic examination findings.

The lesions were classified according to their diagnoses: exostosis, osteoma, cholesteatoma, keratosis obturans, haemangioma, non-neoplastic aural polyp, first branchial cyst and dermatologic disease (malignant external otitis). The presence of EAC occupation in the otological examination and chronic otorrhea as the symptom of presentation were the most relevant exploratory and clinical findings.

Benign EAC lesions are an uncommon and seldom studied cause of temporal bone CT scan requests. Knowing the most relevant clinical and radiological findings is necessary for their proper diagnosis.