A histological examination in the cases of initial diagnosis as chronic otitis media with a polypoid mass in the external ear canal.

OBJECTIVE

to analyse a large series of patients with initial diagnosis of chronic otitis media (COM) with a polypoid mass in the external ear canal (EAC).

MATERIAL AND METHODS

185 consecutive patients with COM were evaluated; 75 showed a polypoid mass in the EAC.

RESULTS

In 65 out of the 75 (86.7%) patients, histological examination after mastoidectomy revealed cholesteatoma. In the remaining 10 (13.3%) cases, the histological diagnosis was: glomus tumor, melanoma, mucosal adenoma, fibrous dysplasia, squamous cell carcinoma, adenoma of the endolymphatic sac, encephalocele, and tuberculosis. One patient (glomus tumor) had undergone biopsy of the polypoid mass twice preoperatively and the initial histological diagnosis was "inflammatory polyp". Therefore, we examined the temporal bones with a glomus tumor diagnosis from the temporal bone collection of the House Ear Institute. In 1560 temporal bones, a glomus tympanicum was found in 6. In four cases, the tumor extended to the EAC mimicking a polyp covered by squamous epithelium.

CONCLUSION

A significant percentage of polyps in COM may be the tip of an 'iceberg'. CT-scan and MRI techniques may be helpful but not always accurate, and biopsies have certain risks. Increased clinical suspicion may limit misdiagnosis and inappropriate management.