Verrucous carcinoma of the renal pelvis with a focus of conventional squamous cell carcinoma.

Verrucous carcinoma (VC) is a rare variant of squamous cell carcinoma (SCC) with an extremely well-differentiated microscopic appearance. It is able to show extensive local invasion, but practically never metastasizes. VCs mostly occur in the oral cavity, larynx, nasal cavity, esophagus, vulva, vagina, anorectal region, penis and skin. VCs sometimes coexist with conventional SCCs, and in these instances they are associated with a higher recurrence rate than pure VCs. The occurrence of VC in the renal pelvis is very rare and to date only 4 cases have been reported. We report here a case of VC with a focus of conventional SCC in the renal pelvis. The patient showed fistula formation by residual tumor in the follow-up period.