Abstract
The goal for the atypical urothelial cells (AUC) category is to capture those cases worrisome for high-grade urothelial carcinoma (HGUC) but that fall short of the suspicious for HGUC (SHGUC) category. Known causes of atypia, such as polyomavirus change, treatment effect, calculi, etc., should be classified as negative for high-grade urothelial carcinoma (NHGUC). We have set forth criteria for AUCs using the cytomorphologic features: increased nuclear to cytoplasmic (N/C) ratio secondary to nuclear enlargement, abnormal nuclear chromasia and chromatin pattern, and irregularity of the chromatinic rim (nuclear membrane). We recommend restraint using the “AUC” category.