Exostoses and osteomas are benign proliferative bone lesions commonly found in the external auditory canal, leading to a progressive narrowing of its lumen.
Although benign, their slow but progressive growth can predispose individuals to external ear infections due to water retention. In some cases, they may even cause hearing loss if the remaining space becomes blocked by earwax or completely occluded by bone growth.
What Are Osteomas?
Osteomas are pedunculated bone neoformations typically located at the tympanosquamous or tympanomastoid sutures. They are isolated lesions of mature bone, usually found in a more external location than exostoses. Their internal structure consists of abundant fibrovascular channels surrounded by irregularly oriented laminated bone.
What Are Exostoses?
Exostoses are more common than osteomas. They are generally multiple and bilaterally symmetrical. These lesions present as broad-based bony elevations (sessile morphology) located in the tympanic bone, specifically in the medial portion of the bony external auditory canal. Their origin is usually reactive, developing in response to external irritants, with the most frequent causes being exposure to cold water and recurrent external ear infections. Histologically, they are characterized by parallel and concentric layers of subperiosteal bone.
Diagnosis of Exostoses and Osteomas
Diagnosis is based on clinical examination. Patients often report symptoms such as ear blockage, earwax retention, recurrent external ear infections, or hearing loss. An initial physical examination may sometimes reveal a hard, stone-like consistency upon palpation. Otoscopy typically identifies a spherical lesion covered by intact epithelium, partially obstructing the external auditory canal. A pure-tone audiometry test usually shows normal results. The rest of the head and neck examination is typically unremarkable.
As a complementary test, computed tomography (CT) scans can be used to assess the extent of the lesions.
Treatment and Surgery
Treatment for exostoses and osteomas is generally conservative, as symptoms are usually mild, and medical management is often effective.
However, for patients experiencing hearing loss, earwax retention, or recurrent external ear infections, surgical treatment may be recommended.
Surgical removal of exostoses is performed when they grow large enough to obstruct the ear canal, leading to infections due to trapped skin and cerumen.
Osteomas are typically not treated unless their size affects hearing due to canal occlusion or leads to repeated infections caused by debris accumulation.
Surgery, which is usually curative, involves the removal of the lesions either through the external auditory meatus or via a retroauricular approach, performed under general anesthesia.
Potential Complications of Surgery
Surgical removal of exostoses or osteomas carries some risks, including:
- Tympanic membrane perforation
- Sensorineural hearing loss
- Facial paralysis
- Stenosis of the external auditory canal
Postoperative Care
After surgery, it is recommended to keep the ear dry until complete healing of the auditory canal, which may take between 1 and 3 months.
At Altiorem, we can assess your case, help prevent complications, and guide you on whether surgical treatment is necessary.