Cholesteatoma or keratoma: A pathological approach

A good knowledge of the pathogenesis of cholesteatoma is as necessary for the otoradiologist as for the otologist. The basic process consists in an ectopic presence in the middle ear of a basal Malpigian like epithelium. Different types of cholesteatoma exist, from the cystic form to the invasive form. While a parameter such as density may vary, the most important information the otologist expects from the radiologist is the definition of bone erosion delineating the extension of this disease.