Increase of diagnosed vestibular schwannoma in Denmark.

The incidence of acoustic neuroma/vestibular schwannoma (VS) in Denmark, with a population of approximately 5 million inhabitants was estimated in 3 periods: June 1976-June 1983, July 1983-June 1990 and July 1990-December 1995. The incidence of tumors increased from 7.8 tumors per million per year in the first period to 9.5 tumors per million per year in the second period. The figure of 12 tumors per million per year is established in the third period. A significant increase of the newly diagnosed intracanalicular and small tumors, with an extracanalicular extension of 1-10 mm was observed in the third period compared with the first 2 periods. Correspondingly a decrease in the newly diagnosed giant tumors was noted in the last 2 periods compared with the first period.