13-years-old, Bichon Frise. Presented with ceruminous adenoma and left chronic otitis externa. A CT-scan of the head was performed.
Description
There is a severe diffuse thickening of the wall of the left external ear canal. This thickening encircles the entire external ear canal at its vertical portion (orange arrows) causing a severe narrowing of the lumen that is visible as a small hypoattenuating line (blue arrows). At the horizontal portion of the external ear canal, there is a moderate focal expansion of the canal, with the thickening affecting mostly the ventral wall (pink arrows), and the lumen is filled with fluid-attenuating, non-contrast enhancing material (green arrows). In addition, there are multiple mineral attenuating foci at the wall of the external ear canal (yellow arrow). Despite the expansion of the external ear canal at its horizontal portion, the lesion in the canal does not invade the adjacent soft tissue structures.
Transverse and dorsal planes
Sagittal planes of the vertical and horizontal portions of the external ear canal.
The same material visible in the lumen of the external ear canal extends into the tympanic bulla, partially occupying its lumen (orange arrows). Otherwise, the left tympanic bulla has normal shape and wall (blue arrows).
The wall of the right external ear canal is mildly diffusely thickened (blue arrows), showing homogeneous post-contrast enhancement, with multiple small mineralizations (orange arrows).
Diagnosis
- Changes in the left external ear canal are consistent with a very severe chronic otitis externa, with the changes in the wall consistent with severe diffuse hyperplasia of the wall of the canal +/- concurrent ceruminous adenoma. Considering the expansion of the horizontal portion of the canal, an incipient malignant process (carcinoma) cannot be excluded, although considered unlikely since there is no evident invasion of the adjacent tissues.
- Extension of the content of the external ear canal into the left tympanic bulla, consistent with left otitis media.
- Mild thickening of the wall of the right external ear canal, without signs of secretion, most likely consistent with degenerative changes secondary to previous otitis externa without evident signs of active infection.
