Papillary urothelial carcinoma of the bladder with exuberant pseudosarcomatous stromal reaction following radiation therapy.

An 82-year-old man, with 6-year history of radical prostatectomy followed by radiotherapy performed for prostatic carcinoma, underwent transurethral resection of a papillary tumor of the bladder lateral walls. Histologically, the lesion displays 2 distinct components: epithelial and stromal. The epithelial component was composed of a noninvasive papillary urothelial carcinoma, predominantly low grade and focally high grade. The stromal component exhibited extensive myxoid changes with increased cellularity but lacking cellular atypia and mitoses. The epithelial component was immunoreactive for pan-cytokeratins and negative for smooth muscle actin (SMA) and vimentin. The stromal component exhibited focal positivity for pan-cytokeratins and SMA, and diffuse immunoreactivity for vimentin. The ki67 reached 70% in the epithelial component and 20% in the stromal component. Papillary intraurothelial carcinoma following radiotherapy may be associated with pseudosarcomatous stromal proliferation. The clinical history and the lack of cellular atypia and mitoses point toward the correct diagnosis.