[Middle ear cholesteatoma: present-day concepts of etiology and pathogenesis].

Since J. Cruveilhier described cholesteatoma as the "pearly" tumor of the middle ear in 1828, the pathogenesis of cholesteatoma remained controversial. It is accepted that cholesteatoma may be congenital or acquired. Several pathogenic mechanisms have been proposed to explain the pathogenesis of congenital cholesteatoma. Proposed theories include ectopic epidermis rest, ingrowth of meatal epidermis, metaplasia and reflux of amniotic fluid. Four basic theories present the pathogenesis of acquired cholesteatoma: invagination of the tympanic membrane (retraction pocket cholesteatoma), basal cell proliferation, epithelial in-growth through a perforation (the immigration theory) and squamous metaplasia of middle ear epithelium. The aim of the article is to review the recent literature dealing with problems of the etiopathogenesis and classification of cholesteatoma.