Morphology in conjunction with immunohistochemistry is sufficient for the diagnosis of mammary analogue secretory carcinoma

Head Neck Pathol. 2015 Mar;9(1):85-95. doi: 10.1007/s12105-014-0557-1. Epub 2014 Jul 31.

Abstract

The recently described mammary analogue secretory carcinoma (MASC) is a low-grade salivary gland malignancy that harbors the recurrent cytogenetic abnormality t(12;15) (p13;q25) ETV6-NTRK3. Confirmation of this is currently considered the gold standard for diagnosis. Some have postulated that morphology together with supporting immunohistochemistry is sufficient to diagnose MASC. In this study we retrospectively review a series of 19 MASCs diagnosed based on histology in conjunction with immunohistochemistry; subsequently we performed in situ hybridization using an ETV6 break-apart probe. Immunohistochemistry for S100 protein and mammaglobin as well as fluorescence in situ hybridization using the Vysis ETV6 Dual Color Break-Apart FISH Probe Kit were performed on all cases. The 19 cases were from 12 females and 7 males with ages ranging from 16 to 76 years (mean = 45 years). Sixteen cases were from the parotid gland, 1 case was from a periparotid lymph node and 2 cases were from the submandibular gland. All 19 cases demonstrated moderate to strong expression of S100 protein. Eighteen cases demonstrated strong, diffuse expression of mammaglobin, while one case had only rare tumor cells that strongly expressed mammaglobin. Eighteen of 19 cases (95 %) demonstrated the ETV6 rearrangement by fluorescence in situ hybridization. Given that morphology together with immunohistochemistry is highly correlated with the ETV6 gene rearrangement, we conclude that molecular confirmation is not required to diagnose MASC.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Female
  • Humans
  • Immunohistochemistry / methods*
  • In Situ Hybridization, Fluorescence
  • Male
  • Mammary Analogue Secretory Carcinoma / diagnosis*
  • Mammary Analogue Secretory Carcinoma / genetics
  • Middle Aged
  • Oncogene Proteins, Fusion / analysis
  • Oncogene Proteins, Fusion / genetics
  • Retrospective Studies
  • Salivary Gland Neoplasms / diagnosis*
  • Salivary Gland Neoplasms / genetics
  • Young Adult

Substances

  • ETV6-NTRK3 fusion protein, human
  • Oncogene Proteins, Fusion