Cytomorphological Effects of Mitomycin C on Urothelial Cells: Eosinophils May Be Clue to The Drug-Induced Changes

Cytomorphological changes of mitomycin C on urothelial cells may be misinterpreted as a neoplastic process. A 60-year old male patient who was given an eight-week course of intravesical mitomycin C due to non-invasive low grade transitional cell carcinoma. During his follow-up care, the findings of a urine cytology exam were as follows: nuclear enlargement of cells, wrinkled nuclear membranes, little hyperchro-masia, pleomorphism, abnormal nuclear morphology and disordered orientation of the urothelium. Furthermore, there were eosinophils nearby the atypical cells. This report aimed at reminding the cytomorphologic changes of mitomycin C may be mis-interpreted as carcinoma, so the presence of eosinophils is required to predict the drug-induced changes