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The authors describe the results of the grading of bladder tumors using morphometry and then compare these with results of histologic grading of the same tumors by different pathologists. Nuclear sizes of cells obtained from superficial and deep cell layers of each carcinoma and from giant cells were measured in 27 cases in which histologic tumor grading by different pathologists was unequivocal. In cells from all three areas, nuclear area increased with higher tumor grade. However, tumors of grades I and II showed significant differences in the size only of the large cells. It is concluded that morphometry is a valuable tool in the objective grading of bladder tumors, with the exception of carcinoma in situ lining the bladder lumen.

Fifty-seven transurethrally resected bladder tumors were analyzed to determine whether different pathologists, using the World Health Organization grading system, graded the same bladder tumor differently (interindividual consistency) and whether the same pathologist graded a bladder tumor differently at different times (intraindividual consistency). Disturbingly high inter- and intraindividual inconsistency in the grading of bladder tumors was found. All pathologists showed essentially the same degree of intraindividual inconsistency: In almost 50 per cent of cases the tumor was graded differently at different times by the same pathologist. The inconsistencies might invalidate the usefulness of bladder tumor grading in clinical decision-making.