Verrucous Carcinoma of Bladder
This variant of squamous cell carcinoma is an indolent, low-grade tumor. The image shows polypoid areas lined by well-differentiated squamous epithelium. It can invade locally with broad, pushing margins but has no capacity to metastasize. However, if it is admixed even focally with conventional squamous cell carcinoma, it is capable of spreading to distant sites.