[Cholesteatoma of the ureter: a case report].

A 68-year-old woman was hospitalized complaining of right flank pain. The excretory pyelogram revealed that the right kidney was hydronephrosis, and a retrograde pyelogram showed stringy filling defects in the middle portion of the right ureter. Suspecting a right ureter tumor, a right ureteronephrectomy was performed. The pathological diagnosis was ureteral cholesteatoma which is a rare condition with reports of only 9 cases in the Japanese literature. Although the possibilities of malignant change has been debatable, long term follow up would be mandatory.