This IS a copy/paste, from PubMed (sorry, not something I focused on over the past 20 years since 1st DX):
In 1683, Duverney first described a temporal bone tumor probably corresponding to a cholesteatoma. Until 1838, when Müller coined the term cholesteatoma, nothing new about this condition appeared in medical publications. After 1838, three main theories about the pathogenesis of cholesteatoma were published. Virchow, in 1855, considered cholesteatoma to be a tumor arising from the metaplasia of mesenchymal cells to epidermal cells, growing then as tumoral cells. Gruber, Wendt, and von Troeltsch, in 1868, considered cholesteatoma to be the result of a metaplasia not of bone cells but of tympanic mucosa cells into a malpighian epithelium. Politzer, in 1869, assumed that cholesteatoma was a glandular neoplasm of middle ear mucosa. Bezold and Habermann, in 1889, considered cholesteatoma to be the result of migration of the external ear canal epidermis into the tympanic cavity via a marginal perforation after acute or chronic otitis. It took 40 years of discussions about these three theories to finally confirm that Habermann and Bezold were correct.