Background: Bladder cytology is being used increasingly to detect and monitor early stage bladder cancer. Because of the lack of significant cytomorphologic atypia in low grade transitional cell carcinomas (TCCs), there often is great difficulty in separating these neoplastic cells from benign urothelial cells.
Methods: In an attempt to increase diagnostic sensitivity, 82 bladder wash specimens, which included 33 low grade TCCs and 49 nonneoplastic lesions, were reviewed retrospectively. With a stepwise logistic regression analysis, three key cytomorphologic criteria useful in the separation of low grade TCC from benign urothelium were identified.
Results: The key cytologic criteria were increased nuclear/cytoplasmic ratios, irregular nuclear borders, and cytoplasmic homogeneity. By using contingency tables, these three criteria combined had a sensitivity of 45% and a specificity of 98% in the diagnosis of low grade transitional cell carcinoma. If any two of the criteria were present, there was a sensitivity of 85% and a specificity of 96%.
Conclusions: By using these three criteria, the diagnosis of TCC can be made with a high degree of accuracy in bladder wash specimens.