[Arthrogenic ear canal tumor].

We report our findings in two female patients (aged 56 and 64 years) who complained about slight hearing loss that varied during jaw movements. In both cases a polypoid tumor of the external auditory meatus was found that almost completely disappeared with mouth opening. CT showed a bony defect of the anterior wall of the external auditory canal in both patients. Biopsies from the tumor-like lesions were done, revealing a chronic inflammatory hyperplasia of the connective tissue in one case and a rheumatic granuloma in the other. Review of medical histories showed that the first patient suffered from a recurrent neurodermatitis and the second had experienced a chronic polyarthritis for many years. From these findings and on the basis of a literature review, we conclude that these pseudotumors represent a chronic inflammatory hyperplasia of the periarticular tissue which herniated through a persistent "foramen of Huschke." This foramen is formed during embryological development of the two tympanic tubercles, but normally closes before the age of 5 years. However, in a few rare cases is may persist to allow herniation of synovial tissue.