title: Mammary analogue secretory carcinoma of salivary glands: a new entity associated with ETV6 gene rearrangement.
abstract: Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumour that harbours the recurrent ETV6-NTRK3 translocation. This is the first series of MASC cases identified in the historic cohort of carcinomas of salivary glands with clinical/pathological correlation and follow-up data. We reviewed 183 primary carcinomas of major and minor salivary glands resected at the Medical University of Gdańsk, Poland, between 1992 and 2012. Based on morphology and immunohistochemistry, cases suspicious for MASC were selected, and the diagnosis was confirmed by fluorescence in situ hybridization (FISH) for ETV6 rearrangement and by RT-PCR for the ETV6-NTRK3 fusion transcript. Seven carcinomas met the criteria of MASC, as they exhibited a typical appearance with solid/microcystic and papillary architecture and intraluminal secretions, and cells completely devoid of basophilic cytoplasmic zymogen granules indicative of true acinar differentiation. The only paediatric case was an unencapsulated tumour composed of macrocystic structures covered by a mostly single but, focally, double layer of cells with apocrine morphology. In all cases, the neoplastic cells revealed immunoreactivity for S100, mammaglobin, cytokeratin CK7, CK8, STAT5a and vimentin. FISH for ETV6 gene rearrangement was positive in six out of seven cases, and RT-PCR was positive in three cases. MASC is a new entity of malignant epithelial salivary gland tumours not included in the 2005 WHO Classification of Head and Neck Tumours. There is a growing body of evidence that it is not as rare as was assumed, as is also indicated by our series (3.8 %). In most cases, MASC shares some microscopic features with AciCC, adenocarcinoma/cystadenocarcinoma NOS and low-grade MEC. In rare cases, MASC with high-grade transformation may mimic the morphological appearances of high-grade salivary gland malignancies, such as salivary duct carcinoma.
authors.affiliation: Department of Pathomorphology, Medical University of Gdańsk, Gdańsk, Poland, hania.majewska@gumed.edu.pl.
authors.forename: Hanna
authors.initials: H
authors.lastname: Majewska
authors.forename: Alena
authors.initials: A
authors.lastname: Skálová
authors.forename: Dominik
authors.initials: D
authors.lastname: Stodulski
authors.forename: Adéla
authors.initials: A
authors.lastname: Klimková
authors.forename: Petr
authors.initials: P
authors.lastname: Steiner
authors.forename: Czesław
authors.initials: C
authors.lastname: Stankiewicz
authors.forename: Wojciech
authors.initials: W
authors.lastname: Biernat
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D002277:Carcinoma / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D050939:Gene Fusion / Q000235:genetics; D015321:Gene Rearrangement / Q000235:genetics*; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D050783:Proto-Oncogene Proteins c-ets / Q000235:genetics* / Q000378:metabolism; D020812:Receptor, trkC / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D009418:S100 Proteins / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism; D012468:Salivary Gland Neoplasms / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D014178:Translocation, Genetic / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism; D055815:Young Adult; D000097764:ETS Translocation Variant 6 Protein
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins; D050783:Proto-Oncogene Proteins c-ets; D020812:Receptor, trkC; D012097:Repressor Proteins; D009418:S100 Proteins; D050799:STAT5 Transcription Factor; D025521:Tumor Suppressor Proteins; D014746:Vimentin; D000097764:ETS Translocation Variant 6 Protein; C494092:STAT5A protein, human