[A case of inverted papilloma of the ureter with malignant findings]

A 70-year-old female with inverted papilloma of the ureter is presented. She was hospitalized because of asymptomatic macrohematuria. Excretory urography and retrograde pyelography demonstrated a filling defect with smooth contour at the mid-portion of the right ureter. Abdominal computer tomographic (CT) scan showed mass lesion (CT number 41) at the same portion as the filling defect. She was diagnosed as having an ureteral tumor and right nephroureterectomy was performed. The gross specimen contained a 24 X 12 mm, polypoid, pedunculated and smooth-surfaced tumor. Pathological diagnosis was inverted papilloma. However, microscopic examination revealed a malignant finding corresponding to transitional cell carcinoma grade 1. From the Japanese and foreign literature, 25 cases of ureteral inverted papilloma were collected and are reviewed. Clinical and pathological features are discussed.