title: Evaluation of chromosomal aberrations in patients with benign conditions and reactive changes in urinary cytology.
abstract: BACKGROUND
  Fluorescence in situ hybridization (FISH) is routinely used to help clarify atypical urinary cytology. However, to the authors' knowledge, little is known regarding the frequency of chromosomal aberrations in non-neoplastic conditions that could potentially lead to false-positive FISH results. The objective of the current study was to evaluate the frequency of chromosomal aberrations in benign cells of the urinary tract using the UroVysion FISH test.
  
  
  METHODS
  The authors analyzed 77 Papanicolaou-stained benign urine cytology specimens with reactive epithelial atypia using a FISH assay detecting the chromosomes 3, 7, and 17 and the gene locus 9p21. A positive test result was defined as an increased copy number of at least 2 chromosomes in ≥ 4 of 25 cells, or > 10 cells with a tetraploid or octaploid pattern, or homozygous or heterozygous deletion of 9p21 (≥ 12cells).
  
  
  RESULTS
  FISH was positive in 27 of 77 bladder washings (35.1%) including 25 of 65 bladder washings (40.5%) and 2 of 15 voided urines (13.5%) from patients with irritative bladder (15 of 36 patients), a history of radiotherapy (7 of 12 patients), nonspecific cystitis (3 of 11 patients), hematuria (3 of 8 patients), and lithiasis (1 of 4 patients) . In 7 of 27 FISH-positive urothelial specimens, the positivity was solely due a polyploid pattern (tetraploid/octaploid pattern) in > 10 of the cells.
  
  
  CONCLUSIONS
  Chromosomal aberrations can occur in reactive urothelial cells, with a tetraploid pattern being the most common. Even an aneuploid pattern of FISH signals does not always prove malignancy because it rarely occurs in reactive urothelial cells. Correlation of FISH results with cytomorphology and patient history is crucial to avoid false-positive diagnoses.
authors: Institute for Pathology, University Hospital of Basel, Basel, Switzerland.
authors: Coya
authors: C
authors: Tapia
authors: Kathrina
authors: K
authors: Glatz
authors: Ellen C
authors: EC
authors: Obermann
authors: Bruno
authors: B
authors: Grilli
authors: Audrey
authors: A
authors: Barascud
authors: Michelle
authors: M
authors: Herzog
authors: René
authors: R
authors: Schönegg
authors: Spasenija
authors: S
authors: Savic
authors: Lukas
authors: L
authors: Bubendorf
mesh_terms: D000328:Adult; D000368:Aged; D000782:Aneuploidy; D002869:Chromosome Aberrations; D002877:Chromosomes, Human; D003581:Cytodiagnosis / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013194:Staining and Labeling; D057891:Tetraploidy; D001743:Urinary Bladder / Q000378:metabolism / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis; D019459:Urothelium / Q000378:metabolism / Q000473:pathology*