title: High grade squamous intraepithelial lesion (CIN 3) with extension into the endocervical clefts. Difficulty of cytologic differentiation from adenocarcinoma in situ.
abstract: OBJECTIVE
  To elucidate the difficulty of cytologically differentiating high grade squamous intraepithelial lesion (SIL) with extension into the endocervical clefts from adenocarcinoma in situ (AIS). Criteria for the cytologic diagnosis of AIS have been delineated. However, it may sometimes be difficult to differentiate between AIS and carcinoma in situ (CIS).
  
  
  METHODS
  We reviewed cervical smears initially diagnosed as glandular intraepithelial neoplasia (GIN) with or without associated SIL CIN; in total, slides from 10 patients were studied. The final diagnosis in two cases was SIL plus GIN, in three cases high grade SIL (HSIL) (CIN 3) plus tubal metaplasia and in five cases HSIL without GIN.
  
  
  RESULTS
  The cervical smears from the last five cases showed, besides features diagnostic of HSIL, the presence of large, crowded sheets with feathering, consisting of fusiform cells with an oval, bare, hyperchromatic nucleus, reminiscent of AIS. At one end of these sheets, normal endocervical cells were sometimes present. In all these cases the cone biopsy revealed HSIL with extension into the endocervical clefts.
  
  
  CONCLUSIONS
  In retrospect, differential diagnosis with AIS is possible in most cases if diagnostic criteria are strictly applied. Indeed, contrary to AIS, feathering is often restricted to one end of the crowded sheets. Moreover, none of these crowded sheets contains glandular openings, and strips and rosettes with pseudostratification are absent.
authors.affiliation: Department of Pathology 1, University Hospital St. Rafael, Katholieke Universiteit, Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Drijkoningen
authors.forename: B
authors.initials: B
authors.lastname: Meertens
authors.forename: J
authors.initials: J
authors.lastname: Lauweryns
mesh_terms: D002584:Cervix Uteri / Q000473:pathology; D005260:Female; D006801:Humans; D009361:Neoplasm Invasiveness; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D002578:Uterine Cervical Dysplasia / Q000145:classification / Q000473:pathology*