[A case of inverted papilloma with subsequent heterotopical recurrence of transitional cell carcinoma].

A case of inverted papilloma with subsequent heterotopical recurrence of inverted type transitional cell carcinoma is reported. A 24-year-old man had a medical examination of our hospital with chief complaint of asymptomatic macroscopic hematuria on October 23, 1982. Cystoscopy revealed a smooth surfaced and finger-tip sized tumor at the bladder neck. Because of the large bulk and the location of the tumor, the tumor was resected through cystotomy. After histological examination, the tumor was diagnosed as inverted papilloma. Cystoscopy was repeated every 3-6 months. The tumor recurred 4 times heterotopically, 19, 35, 43 and 53 months after the initial surgery. The pathological examinations of these tumor specimens showed transitional carcinoma mostly of inverted growth. Most of the urologists and pathologists believe inverted papilloma to be a benign neoplasm, but several reports and this case suggest the possibility of recurrence and malignant transformation of inverted papilloma.