Chronic mastoiditis and otitis externa maligna due to blockage oft the mastoid antrum caused by an intratympanal facial nerve schwannoma

Introduction Intratympanal facial nerve schwannomas without facial palsy are usually a coincidental intraoperative finding. Aeration and drainage disorders caused by the tumor can lead to chronic inflammatory processes.

Casuistry A 56-year-old patient presented with otalgia, purulent otorrhea and progressive hearing loss on the left that had been present for several months. Already in the previous year alio loco a retroauricular tympanomastoidectomy was performed because of similar symptoms on this ear. Pre-existing conditions include type 1 diabetes and requirement for dialysis.

The ENT examination showed the full picture of otitis externa maligna with evidence of P. aeruginosa as well as a central eardrum defect. Pure tone audiometry identified a pantonal air-bone-gap of up to 50 dB ipsilaterally. The CT showed a soft tissue mass shadow of the remaining mastoid cells and the epitympanic area.

There was no improvement after intravenous antibiotic therapy and local treatment. Therefore we performed retroauricular tympanomastoidectomy. During surgery, a cholesteatom-like tumor intratympanal surrounded the incus and the facial nerve. The incus had to be resected to completely remove the tumor while preserving the facial nerve. The ossicular chain was reconstructed by stapes elevation with cartilage. Immunohistologically, the tumor was confirmed as a schwannoma. Postoperative controls showed a complete functional preservation of the nerve.

Conclusion The case illustrates the pathophysiological significance of the drainage oft he mastoid antrum. The entire symptomatology can be derived as a consequence of the increasing blockage by the schwannoma, which led to a chronic inflammatory reaction with mastoiditis and otitis externa maligna in this patient.

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Publication History

Article published online:
10 June 2020