A Parotid Gland Mammary Analogue Secretory Carcinoma in a 4-Year-Old Boy: Case Report and Literature Review

Fetal Pediatr Pathol. 2023 Apr;42(2):342-350. doi: 10.1080/15513815.2022.2116621. Epub 2022 Sep 2.


Background: Mammary analogue secretory carcinoma (MASC) is characterized by similar histologic, immunohistochemical, and molecular features with breast secretory carcinoma. MASC usually occurs in adults. Case report: A 4-year-old boy presented with a right infra-auricular mass. Features of the tumor include solid, tubular, and papillary growth patterns, with homogenous eosinophilic secretions inside microcystic structures. Immunohistochemical stains showed strong, diffuse staining for CK7, S100, pan-TRK protein. P63 was positive in a peripheral pattern. Fluorescence in situ hybridization (FISH) analysis showed the characteristic ETV6-NTRK3 gene fusion. Conclusion: Typical histological, immunohistochemical, and molecular features are present in MASC occurring early in childhood.

Keywords: ETV6-NTRK3 fusion; Mammary analogue secretory carcinoma (MASC); pediatric patient; salivary gland tumor.

Publication types

  • Review
  • Case Reports

MeSH terms

  • Biomarkers, Tumor / metabolism
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Mammary Analogue Secretory Carcinoma* / diagnosis
  • Mammary Analogue Secretory Carcinoma* / genetics
  • Mammary Analogue Secretory Carcinoma* / pathology
  • Oncogene Proteins, Fusion / genetics
  • Parotid Gland / chemistry
  • Parotid Gland / metabolism
  • Parotid Gland / pathology
  • Salivary Gland Neoplasms* / genetics
  • Salivary Gland Neoplasms* / metabolism
  • Salivary Gland Neoplasms* / pathology


  • Oncogene Proteins, Fusion
  • Biomarkers, Tumor