Atypical squamous cells in urine cytology are associated with a significant risk of high-grade malignancy.

ASC in urine cytology is a significant finding and is associated with a high ROHM. In the absence of accompanying UCA, LG squamous atypia had a lower ROHM than HG atypia. In the presence of UCA, LG and HG squamous atypia had ROHMs of over 90%. These findings suggest that ASC and their grade of atypia should be noted in the cytology report, and clinicians should be made aware of their clinical significance.