title: Comprehensive Cytomorphologic Analysis of Pulmonary Adenoid Cystic Carcinoma: Comparison to Small Cell Carcinoma and Non-pulmonary Adenoid Cystic Carcinoma.
abstract: BACKGROUND
  Cytologic diagnosis of pulmonary adenoid cystic carcinoma (AdCC) is frequently challenging and differential diagnosis with small cell carcinoma is often difficult.
  
  
  METHODS
  Eleven cytologically diagnosed cases of pulmonary AdCC were collected and reviewed according to fifteen cytomorphologic characteristics: small cell size, cellular uniformity, coarse chromatin, hyperchromasia, distinct nucleolus, frequent nuclear molding, granular cytoplasm, organoid cluster, sheet formation, irregular border of cluster, hyaline globule, hyaline basement membrane material, individual cell necrosis or apoptotic body, and necrotic background. Twenty cases of small cell carcinoma and fifteen cases of non-pulmonary AdCC were also reviewed for the comparison.
  
  
  RESULTS
  Statistically significant differences were identified between pulmonary AdCC and small cell carcinoma in fourteen of the fifteen cytomorphologic criteria (differences in sheet formation were not statistically significant). Cellular uniformity, distinct nucleolus, granular cytoplasm, distinct cell border, organoid cluster, hyaline globule, and hyaline basement membrane material were characteristic features of AdCC. Frequent nuclear molding, individual cell necrosis, and necrotic background were almost exclusively identified in small cell carcinoma. Although coarse chromatin and irregular cluster border were observed in both, they favored the diagnosis of small cell carcinoma. Hyaline globules were more frequently seen in non-pulmonary AdCC cases.
  
  
  CONCLUSIONS
  Using the fifteen cytomorphologic criteria described by this study, pulmonary AdCC could be successfully distinguished from small cell carcinoma. Such a comprehensive approach to an individual case is recommended for the cytologic diagnosis of pulmonary AdCC.
authors.affiliation: Department of Pathology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Seokhwi
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Pathology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jinah
authors.initials: J
authors.lastname: Chu
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hojoong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Pathology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
keywords: Carcinoma, adenoid cystic; Carcinoma, small cell; Cytology; Lung