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). 185 consecutive patients with COM were evaluated; 75 showed a polypoid mass in the EAC. 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. 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. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.