The histopathology of mastoidectomy cavities, with particular reference to persistent disease leading to chronic otorrhoea.

Open cavity mastoidectomy remains the principal surgical treatment of middle ear cholesteatoma in the United Kingdom. A significant proportion of mastoid cavities are prone to intermittent or continuous discharge. In this study the histopathological features of material removed from 159 mastoid cavities at revision surgery were reviewed. Findings included squamous epithelium with acute and chronic inflammation, foreign body granuloma and aural polyps. Of particular note was the very infrequent finding of discharging cavities lined with respiratory epithelium, suggesting that retained mucosa in mastoid air cells is not a common cause of persistent otorrhoea.