Borderline Brenner Tumor
Comments:
Borderline Brenner tumor consisting of proliferating nests of transitional cells in a fibromatous stroma. Some authors distinguish between proliferating Brenner tumor which lacks significant cytologic atypia and resembles low-grade papillary urothelial carcinoma and borderline Brenner tumor which can have severe cytologic atypia and resemble high-grade urothelial carcinoma. In either case, there is no stromal invasion.