Epidemiology and aetiology of middle ear cholesteatoma.

A total of 500 patients with cholesteatoma diagnosed and operated during 1982-91 in the region of Tampere University Hospital and Mikkeli Central Hospital in Finland were analysed retrospectively. The mean annual incidence was 9.2 per 100,000 inhabitants (range 3.7-13.9) and during the study period the annual incidence decreased significantly. The incidence was higher among males under the age of 50 years. There was no accumulation of cholesteatoma diseases in lower social groups. The majority (72.4%) of cholesteatoma patients had suffered from otitis media episodes. Tympanostomy was carried out in 10.2% and adenoidectomy or adenotonsillectomy in 15.9% of all cholesteatoma ears prior to cholesteatoma surgery. Cholesteatoma behind an intact tympanic membrane with no history of otitis media was verified in 0.6% of patients and in cleft palate patients in 8%. In this study, 13.2% of patients had ear trauma or ear operation in anamnes.