Osteomas of the external auditory canal are benign bony tumours arising from the tympanic bone.
The etiology of osteomas is unknown. They are considered to be a true benign bony tumour and, unlike exostoses, osteomas do not develop as a reactive phenomenon.
Unlike exostoses, osteomas usually trap wax and keratin debris in the deep meatus, thereby producing a conductive hearing loss.
Unlike exostoses, osteomas are usually solitary, appearing as a bony hard sessile mass covered by normal deep canal skin. The `bony' nature of these tumours can readily be determined by palpation.
If an osteoma becomes symptomatic by occluding the lumen of the canal or by trapping wax and keratin debris within the canal, it should be removed.
Note the large solitary osteoma which is extending out into the lumen of the cartilaginous canal.