Bladder cancer as seen in giant histologic sections.

Giant sections from cystectomy specimens in 45 cases of bladder cancer were examined microscopically after en bloc fixation and processing. There were 35 transitional cell, seven squamous cell, and three mixed transitional cell and squamous carcinomas. Broad front invasion was associated with papillary and superficial tumors while tentacular invasion was associated with solid tumors and a generally poorer prognosis. Carcinoma in situ merged with the invasive cancer in 33 cases, and neoplasia in these cases tended to be multifocal. In 10 cases there was no carcinoma in situ next to the invasive lesion, and the cancer was unifocal. These findings support the concept that there may be two pathogenetic types of bladder cancer, one arising in an extensive field of abnormal epithelium and one arising in a focal area of abnormality. The findings also underscore the importance in clinical management of selected mucosal biopsies adjacent to the site of any visible bladder tumors.