Infiltrative areas are seen in approximately one-third of cases of urothelial carcinoma. The invasive component usually consists of nests, cords, clusters, or individual tumor cells arising from the base of the lesion. Invasion is more often seen with high-grade tumors. Non-invasive papillary urothelial carcinomas (pathologic Stage Ta) and Stage T1 tumors (invasion confined to lamina propria) are usually managed by transurethral resection. Early cystectomy may be considered if the tumor is high-grade, bulky, or multifocal, has lymphovascular invasion, or micropapillary histology.