title: Clinical impact of atypical squamous cells of undetermined significance. A cytohistologic comparison.
abstract: OBJECTIVE
  To assess the percentage of squamous intraepithelial lesions (SILs) in the atypical squamous cells of undetermined significance (ASCUS) cytologic diagnosis.
  
  
  METHODS
  From January 1994 to December 1995, 421 cervical Pap smears with a diagnosis of ASCUS were followed with cervical biopsies within three months. The ASCUS cytologic diagnosis was correlated with the histologic findings and stratified according to age group, previous abnormal history and cell type of ASCUS (squamoid vs. metaplastic).
  
  
  RESULTS
  Histologic diagnosis showed that of ASCUS diagnoses, 13% were normal, 34% were reactive, 4.8% were atypical, 43% were low grade SIL, 4% were high grade SIL, 1% were carcinoma in situ, and none were invasive lesions. The patients in the youngest group, up to 25 years, demonstrated the highest percentage of SIL. Patients with a previous abnormal gynecologic history showed a higher percentage of SIL than those without an abnormal history. SILs were observed in 51.5% of squamoid ASCUS and 36.5% of metaplastic ASCUS.
  
  
  CONCLUSIONS
  Forty-eight percent of females having an ASCUS diagnosis on Pap smears had SIL and thus a preneoplastic lesion. The highest percentage of SIL was found in females 25 years and younger. Our findings suggest that an ASCUS diagnosis warrants ongoing follow-up.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Loma Linda University, California 92350, USA.
authors.forename: V
authors.initials: V
authors.lastname: Lousuebsakul
authors.forename: S M
authors.initials: SM
authors.lastname: Knutsen
authors.forename: I T
authors.initials: IT
authors.lastname: Gram
authors.forename: M R
authors.initials: MR
authors.lastname: Akin
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002584:Cervix Uteri / Q000473:pathology*; D003937:Diagnosis, Differential; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D018307:Neoplasms, Squamous Cell / Q000473:pathology*; D065006:Papanicolaou Test; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis / Q000473:pathology*; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D014626:Vaginal Smears