Mammary analog secretory carcinoma, low-grade salivary duct carcinoma, and mimickers: A comparative study

Todd M. Stevens, Andra O. Kovalovsky, Claudia Velosa, Qiuying Shi, Qian Dai, Randall P. Owen, Walter C. Bell, Shi Wei, Pamela A. Althof, Jennifer N. Sanmann, Larissa Sweeny, William R. Carroll, Gene P. Siegal, Martin J. Bullock, Margaret Brandwein-Gensler

Research output: Contribution to journalArticlepeer-review

64 Scopus citations

Abstract

Mammary analog secretory carcinoma (MASC) is a recently recognized low-grade salivary carcinoma characterized by a specific ETV6 rearrangement. We describe 14 new MASCs and examine their immunophenotypic and genetic profiles in the context of look-alikes, namely, low-and high-grade salivary duct carcinoma and acinic cell carcinoma. ETV6 rearrangement, and robust expression of mammaglobin and S100, were demonstrated in 11/11, 14/14, and 12/14 MASCs, respectively. All low-grade salivary duct carcinomas coexpressed S100/mammaglobin (6/6); none harbored ETV6 rearrangements (0/5). Given that S100/mammaglobin coexpression and absence of zymogen granules are features of both MASC and low-grade salivary duct carcinoma, these two are best distinguished histologically. The former is predominantly an extraductal neoplasm with bubbly pink cytoplasm, whereas the latter is a distinct intraductal micropapillary and cribriform process. Querying ETV6 gene status may be necessary for difficult cases. No acinic cell carcinoma expressed mammaglobin (0/13) or harbored an ETV6 rearrangement (0/7); only 1/13 acinic cell carcinomas weakly expressed S100. DOG1 expression was limited or absent among all tumor types, except acinic cell carcinoma which expressed DOG1 diffusely in a canalicular pattern. Therefore, histology and immunohistochemistry (mammaglobin, S100, DOG1) suffices in distinguishing acinic cell carcinoma from both MASC and low-grade salivary duct carcinoma. HER2 (ERBB2) amplification was detected in only 1/10 acinic cell carcinomas, but none of the MASCs or low-grade salivary duct carcinomas tested. High-grade salivary duct carcinomas frequently expressed mammaglobin (11/18) and harbored HER2 amplifications (13/15); none harbored ETV6 rearrangements (0/12). High-grade salivary duct carcinomas can easily be distinguished from these other entities by histology and HER2 amplification.

Original languageEnglish (US)
Pages (from-to)1084-1100
Number of pages17
JournalModern Pathology
Volume28
Issue number8
DOIs
StatePublished - Aug 1 2015

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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