泌尿上皮倒生性乳頭瘤－罕見病例報告與文獻回顧

吳冠賢^1,2, 李政學^1,2*

¹高雄醫學大學附設中和醫院 泌尿部、²高雄醫學大學 臨床醫學研究所

Inverted urothelial papilloma in bladder: Case report and review of literature

Kuan-Hsien Wu^1,2, Cheng-Hsueh Lee^1,2*

¹ Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan

² Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

Introduction: Inverted urothelial papilloma (IUP) is a rare tumor in adults as a non-invasive, endophytic urothelial neoplasm. Although it was characterized a benign entity, IUP is associated with secondary development of urothelial carcinoma (UC), recurrence of disease, or presence of synchronous UC. It is important to recognize the diagnostic criteria and common morphological variants of IUP to distinguish it from UC or other reactive lesions.

Case report: A 60-year-old man presented with lower urinary symptoms, frequency and nocturia for several weeks, but no hematuria. Prostate-specific antigen (PSA) was within normal levels. Transrectal ultrasound scan (TRUS) depicted a bladder mass found close to the bladder neck. Urine cytology showed no evidence of high-grade urothelial carcinoma. Cystoscopy revealed a pedunculated bladder mass with a smooth surface at the left lateral wall. The patient received surgical intervention for tumor excision. The pathologic report showed an inverted urothelial papilloma, with irregular, downward growing ramifying thin and orderly cords and sheets arising from the overlying urothelium. The cords had peripheral palisades of basaloid cells. There was no discernible cytologic atypia or mitotic activity. CK20 immunostaining was negative and the p53 protein was maintained at a low level. After surgery, his symptoms improved significantly. Currently, no recurrence was encountered under one year regular out-patient department follow up.

Conclusion: IUP is a rare but benign disease. The definite preoperative diagnosis is difficult. Our report demonstrated an IUP found during TRUS. Even lower urinary symptoms can be the possible cause of bladder lesions. Immunohistochemistry and molecular studies can also be helpful in differentiating the IUP and UC.