Cholesteatoma of the ear is a well recognized entity, but it is not well known that cholesteatoma may occur in other areas of the body, including the intestinal tract, brain, genitalia, skin, eye, sinuses, and kidney. Cholesteatomas originating in areas such as the brain are considered to be true tumors, arising from anlage rests. In the ear and kidney, however, the origin is generally felt to be associated with chronic infection causing squamous metaplasia. The keratin or cornified material shed by the squamous epithelium may be passed in the urine as “flakes of skin” or be retained within the kidney as a mass of keratin. When the keratin accumulates in the kidney in association with squamous metaplasia, the condition is known as cholesteatoma. The flakes of keratin present a stringy or mottled appearance on the pyelogram. Since the original description of cholesteatoma of the kidney by Rokitansky in 1861, 10 cases have been reported, most of them without radiographs and none in the radiological literatu...