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Bladder tumors vary from pre-cancerous, chronic, hyperplastic inflammation (cystitis) to benign papillomas and malignant carcinomas. ’Transitional carcinoma’ is the most common name given to tumors of the lining of the urinary tract with ’urothelial carcinoma’ sometimes used for those arising outside the bladder (in the urethra). There is gradation and progression from the benign to malignant types so both hyperplasia and metaplasia (change from the normal type of tissue) are regarded as pre-malignant. Animals with malignant tumors do not usually survive longer than a year. Less commonly cancer may arise from the muscle of the bladder. These tumors rarely metastasize.