Surgical Pathology Criteria

Urothelial (Transitional Cell) Carcinoma In Situ (including flat hyperplasia and dysplasia)

Differential Diagnosis

Urothelial Carcinoma In Situ Reactive Atypia
Cytologically malignant Generally more uniform atypia, not clearly malignant
≥25% of nuclei ≥5x size of lymphocytes Nuclei only 2x size of lymphocytes
Nucleoli if present usually variable, excentric Nucleoli usually uniform and centrald
Inflammation variably present Inflammation always present, acute or chronic
Mitotic figures may be atypical Mitotic figures may be frequent but not atypical
Both may be either hyperplastic or largely denuded due to sloughing

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