title: Improved risk stratification for patients with high-grade urothelial carcinoma following application of the Paris System for Reporting Urinary Cytology.
abstract: BACKGROUND
  The Paris System for Reporting Urinary Cytology (TPS) requires 4 cytomorphologic criteria for a definitive diagnosis of high-grade urothelial carcinoma (HGUC) in urinary tract cytology (UTC) specimens: an elevated nuclear-to-cytoplasmic (N/C) ratio (at or above 0.7), markedly atypical nuclear borders, moderate to severe hyperchromasia, and coarse chromatin. However, malignant UTC specimens often contain degenerative changes, and this limits the number of malignant cells meeting all 4 TPS cytomorphologic criteria.
  
  
  METHODS
  One hundred twelve UTC specimens from patients with a subsequent diagnosis of HGUC were reviewed and reclassified according to TPS criteria. The presence of TPS cytomorphologic criteria for HGUC in each specimen was recorded, as was the proportion of atypical cells meeting all 4 criteria.
  
  
  RESULTS
  The number of specimens definitively diagnosed as HGUC did not significantly change upon reclassification. However, approximately 40% of indeterminate specimens (21 of 51) were reclassified into a higher risk category. The most restrictive cytomorphologic criterion was an N/C ratio of 0.7 or higher (seen in 78% of specimens), and approximately half of specimens containing all 4 cytomorphologic criteria did not meet TPS's numerical criterion for HGUC (at least 5 malignant cells). In the majority of specimens qualifying for HGUC by TPS standards, only a small fraction of atypical cells (10%-20%) met all the criteria.
  
  
  CONCLUSIONS
  When applied to malignant UTC specimens, TPS criteria improved specimen risk stratification by upgrading approximately 40% of indeterminate specimens into higher risk categories while not significantly changing the frequency of HGUC diagnoses. Cancer Cytopathol 2017;125:427-34. © 2017 American Cancer Society.
authors.affiliation: Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Morgan L
authors.initials: ML
authors.lastname: Cowan
authors.affiliation: Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Dorothy L
authors.initials: DL
authors.lastname: Rosenthal
authors.affiliation: Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Christopher J
authors.identifier: http://orcid.org/0000-0002-8822-5655
authors.initials: CJ
authors.lastname: VandenBussche
mesh_terms: D000368:Aged; D002278:Carcinoma in Situ / Q000473:pathology* / Q000652:urine; D002295:Carcinoma, Transitional Cell / Q000473:pathology* / Q000652:urine; D003581:Cytodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D012189:Retrospective Studies; D018570:Risk Assessment; D014556:Urine / Q000166:cytology; D014571:Urologic Neoplasms / Q000473:pathology* / Q000652:urine
keywords: The Paris System; bladder cancer; urinary tract; urine; urothelial carcinoma