Squamous papilloma of the urinary tract is unrelated to condyloma acuminata.

BACKGROUND: To the authors' knowledge, there is no previous report of squamous papilloma of the urinary tract. It is uncertain whether there is a correlation between squamous papilloma, condyloma acuminatum, and verrucous carcinoma.

METHODS: The authors evaluated the clinical and pathologic features of squamous papilloma (5 of the bladder, 2 of the urethra), condyloma acuminatum (3 cases), and verrucous carcinoma (3 cases) of the urinary bladder and performed human papillomavirus (HPV) DNA in situ hybridization studies to determine whether HPV was a common feature shared by these lesions. In addition, DNA ploidy evaluation by image cytometry and p53 immunohistochemical staining were performed.

RESULTS: Squamous papilloma of the urinary tract occurred in elderly women and followed a benign clinical course with infrequent recurrence. All squamous papillomas were HPV DNA negative and DNA diploid with no or minimal p53 nuclear accumulation. Condyloma acuminata of the bladder contained HPV DNA, increased p53 protein expression, and aneuploid DNA content. All three cases of condyloma acuminata were associated with coexistent condylomata of the external genitalia, and two required pelvic exenteration for uncontrolled expansile growth. Verrucous carcinoma of the bladder occurred in elderly patients. All three cases of verrucous carcinoma were negative for HPV DNA and DNA aneuploid, and they exhibited consistent p53 expression.

CONCLUSIONS: These data indicate that squamous papilloma is a distinct entity not related to condyloma or verrucous carcinoma. These lesions are benign, HPV DNA negative, DNA diploid, and they lack p53 overaccumulation.