Squamous and/or glandular differentiation in urothelial carcinoma: prevalence and significance in transurethral resections of the bladder.

BACKGROUND: It is controversial if urothelial carcinoma of the bladder with squamous and/or glandular differentiation is a more aggressive neoplasm than conventional urothelial carcinoma.
DESIGN: A total of 165 transurethral resections of the bladder were reviewed. A group with squamous and/or glandular differentiation was compared to a group without this finding. The chi-square test was used to assess the association of the groups with stage (TNM, 1997).
RESULTS: Of the total of 165 transurethral resections of the bladder, 153 (92.72%) were conventional urothelial carcinomas and 12 (7.27%) showed squamous and/or glandular differentiation. The distribution according to stage was 84 (54.9%), 35 (22.9%) and 34 (22.2%) for the group without differentiation and 0 (0%), 3 (25%) and 9 (75%) for the group with squamous and/or glandular differentiation, respectively for stages pTa, pT1 and pT2. Tumors with squamous and/or glandular differentiation showed a significant statistical correlation to higher stage at clinical presentation (p < 0.0001). There was no significant statistical relation according to age (p = 0.8433), sex (p = 0.5672) or race (p = 0.3137).
CONCLUSIONS: The results suggest that urothelial bladder carcinomas with squamous and/or glandular differentiation are more aggressive neoplasms. There was a significant statistical correlation between tumors with this differentiation and higher stage at clinical presentation.