The Pathology of Human Bladder Cancer

The pathologist plays a key role in the detection and diagnosis of bladder cancer, as well as in the development of strategies for the clinical management of this disease by the urologist. In order to make appropriate decisions, the urologist needs help from the pathologist in determining: 1) whether or not a bladder tumor is present; 2) if present, its histologic type, grade, depth of invasion and evidence of lymphatic or blood vessel invasion; 3) whether or not there are associated neoplastic lesions elsewhere in the bladder -or elsewhere in the lower urinary tract; and 4) if some therapeutic modality has been directed toward the neoplastic tissue, the completeness of tumor removal or destruction. It is recommended that the WHO classification of bladder tumors be used by pathologists in their reports to facilitate communication among pathologists, urologists, radiation therapists, medical oncologists, and others involved in the management of bladder cancer patients. In addition, the pathologist should make a definite statement regarding the presence or absence of muscle tissue in every bladder biopsy specimen containing tumor. After one or more superficial tumors are identified by the urologist and treated by transurethral means, management of the patient will depend not only on the microscopic evaluation of the resected tumor but also on an accurate assessment of the neoplastic potential of the remaining epithelium. The cytopathologic examination of urine samples or bladder washings aids this assessment.