Affiliation:
1. Department of Pathology, Cedars Sinai Medical Center, Los Angeles, California, United States,
Abstract
High-grade urothelial carcinoma (HGUC) is a clinically aggressive form of cancer that poses a high risk of progressing to invasive carcinoma. Urine cytology is a powerful tool for diagnosing HGUC and for monitoring patients with established HGUC. The Paris System is the standard diagnostic terminology for urine cytology. The diagnostic criteria for HGUC include nuclear enlargement with a high nuclear-to-cytoplasmic ratio of 0.7 or greater, moderate-to-severe hyperchromasia, irregular nuclear membrane outlines, and coarse/clumped chromatin, in at least 5–10 malignant cells. Various variants of high-grade malignant cells are also recognized. Urothelial carcinoma with divergent differentiation and histologic subtypes may also be identified using urine cytology, with an emphasis on recognizing aggressive subtypes such as micropapillary, plasmacytoid, and sarcomatoid subtypes. Diagnosing HGUC in upper urinary tract urine specimens is particularly challenging and may have significant surgical consequences. It requires identifying more than ten diagnostic cells to confirm the diagnosis. Therefore, a high degree of expertise and experience is required to accurately diagnose HGUC using urine cytology, particularly for upper urinary tract specimens.