title: Cytologic Features of ALK-Positive Pulmonary Adenocarcinoma.
abstract: BACKGROUND
  The aim of this study was to determine the cytologic features of anaplastic lymphoma kinase (ALK) expressing pulmonary adenocarcinoma.
  
  
  METHODS
  We analyzed the cytopathological findings of 15 cases of endobronchial ultrasound guided aspiration and a case of bronchial washing. These cases were selected based on the histomorphology of ALK-rearranged lung adenocarcinoma.
  
  
  RESULTS
  Cytology showed mucinous (81.3%) and hemorrhagic (50%) backgrounds. The cells were arranged in tubulopapillary or tubulocribriform patterns (93.8%), and clusters (56.3%) admixed with signet ring cell features (87.5%). The tumor cells were monotonous and uniform with vesicular nuclei and a small nucleolus.
  
  
  CONCLUSIONS
  The characteristic findings were sheets showing a tubulopapillary or tubulocribriform appearance, with vesicular nuclei and a bland chromatin pattern (p<0.001). Scattered signet ring cells were helpful in suggesting ALK-positive adenocarcinoma (p<0.001).
authors.affiliation: Department of Pathology, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Seung Yeon
authors.initials: SY
authors.lastname: Ha
authors.forename: Jungsuk
authors.initials: J
authors.lastname: Ahn
authors.forename: Mee Sook
authors.initials: MS
authors.lastname: Roh
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
authors.forename: Jae Jun
authors.initials: JJ
authors.lastname: Lee
authors.forename: Boin
authors.initials: B
authors.lastname: Lee
authors.forename: Jun
authors.initials: J
authors.lastname: Yim
keywords: Adenocarcinoma; Anaplastic lymphoma kinase; Carcinoma, non-small-cell lung; Cytology; Lung