title: Finding and characterizing mammary analogue secretory carcinoma of the salivary gland.
abstract: BACKGROUND
  A new tumor entity of the salivary glands, mammary analogue secretory carcinoma (MASC) with ETV6-NTRK3 translocation, has recently been proposed. MASC was originally diagnosed as adenocarcinoma, not otherwise specified (ANOS), or acinic cell carcinoma (AciCC) by the current World Health Organization classification. We aimed to identify MASC cases by molecular tests, and to characterize their clinical, histological, and immunohistochemical features.
  
  
  METHODS
  Thirty cases of MASC candidates were selected after review of 196 salivary gland tumors, and subjected to break-apart ETV6 fluorescence in situ hybridization (FISH), and immunohistochemical study for S100 protein, gross cystic disease fluid protein 15, DOG1, estrogen receptor, and progesterone receptor.
  
  
  RESULTS
  Valid FISH results were obtained in 23 cases, and 13 positive cases were retrieved. MASCs were histologically varied, and the most frequent features observed in 10 cases were low-grade papillary/cystic/glandular patterns, intraluminal secretory materials, ovoid/wrinkled nuclei, and relatively abundant granular eosinophilic cytoplasms, corresponding to papillary-cystic or follicular types of AciCC. All cases showed diffuse immunopositivity for S100 protein. Three cases developed recurrences, but all patients remained alive.
  
  
  CONCLUSIONS
  MASC could be a molecularly well-defined salivary gland neoplasm, encompassing some portions of AciCC and ANOS, but its histological spectrum and clinical implication require further investigation.
authors.affiliation: Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Jung
authors.forename: Joon Seon
authors.initials: JS
authors.lastname: Song
authors.forename: Sang Yoon
authors.initials: SY
authors.lastname: Kim
authors.forename: Soon Yuhl
authors.initials: SY
authors.lastname: Nam
authors.forename: Jong-Lyel
authors.initials: JL
authors.lastname: Roh
authors.forename: Seung-Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Sung-Bae
authors.initials: SB
authors.lastname: Kim
authors.forename: Kyung-Ja
authors.initials: KJ
authors.lastname: Cho
keywords: Carcinoma, acinar cell; ETV6-NTRK3 fusion protein, human; In situ hybridization, fluorescence; Salivary gland neoplasms