Atypical urothelial cells (bladder washing, ThinPrep, Papanicolaou stain, 600×). This urine specimen has very rare cells with slightly higher N/C ratio (>0.5), in addition to hyperchromasia. In this atypical cell cluster (arrow) cells are enlarged compared with the neighboring clusters of benign urothelial cells. Degenerative changes make it difficult to further characterize the chromatin pattern. However, the cytomorphologic changes are sufficient to classify this case under ‘AUC'.