Verrucous carcinoma of the bilharzial bladder. Impact of invasiveness on survival.

Verrucous carcinoma of bilharzial bladder, a rare neoplasm, is regarded as a distinct variant of squamous cell carcinoma. We studied 37 cases treated with cystectomy in the past 15 years. Despite previous reports of no local invasion and no local recurrence or distant metastasis postoperatively, we observed 60% of focal tumour transformation into invasive squamous cell carcinoma. Such transformation and dedifferentiation to squamous cell carcinoma can be expected in a high proportion of these tumours. The survival rate in the invasive cases was approximately the same as in squamous cell carcinoma. Non-surgical management or adjuvant treatment to surgery are inappropriate in verrucous bladder carcinoma. Radical cystectomy is the only standard treatment offering cure.