Mammary analogue secretory carcinoma of salivary glands is a lipid-rich tumour, and adipophilin can be valuable in its identification.
OBJECTIVE
Mammary analogue secretory carcinoma (MASC) of salivary glands shows morphological similarities to milk-secreting mammary epithelial cells. The aim of this study was to analyse the immunohistochemical expression of adipophilin (a component of milk lipid globule membranes) and of proteins related to secretory mechanisms (STAT5a and mammaglobin) in MASC and other salivary tumours.


RESULTS
Ten cases of MASC (all with ETV6 translocation) and 83 other salivary carcinomas were studied. In all MASC cases, adipophilin stained numerous large lipid droplets. These droplets were minute in other salivary carcinomas, except for sebaceous carcinoma. Overexpression of STAT5a was detected in all MASC cases, but only occasionally in other carcinomas. Mammaglobin expression occurred frequently in MASC (70% of cases), whereas, in other carcinomas, it was uncommon and limited. Only MASC showed cytoplasmic reactivity for p63, particularly in papillary-cystic areas. Positivity for S100, vimentin and high molecular weight keratin was observed in 100% of MASC cases.


CONCLUSIONS
MASC is a lipid-rich tumour containing large lipid droplets covered by adipophilin. This finding can be included among its defining immunohistochemical features, and possibly represents lactation-like secretory differentiation. Strong expression of STAT5a and cytoplasmic p63 in MASC reinforces this hypothesis.
Department of Pathology, Medical Sciences Faculty, University of Campinas (UNICAMP), Campinas, Brazil.
Fernanda Viviane
FV
Mariano
Harim Tavares
HT
dos Santos
Wilson Delgado
WD
Azañero
Isabela Werneck
IW
da Cunha
Claudia Malheiros
CM
Coutinho-Camilo
Oslei Paes
OP
de Almeida
Luiz Paulo
LP
Kowalski
Albina
A
Altemani
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis*; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D000070780:Perilipin-2; D012468:Salivary Gland Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult; D020812:Receptor, trkC; D000097764:ETS Translocation Variant 6 Protein
D014408:Biomarkers, Tumor; D008565:Membrane Proteins; D015514:Oncogene Proteins, Fusion; D000070780:Perilipin-2; C484319:ETV6-NTRK3 fusion protein, human; D020812:Receptor, trkC; D000097764:ETS Translocation Variant 6 Protein; C000602982:PLIN2 protein, human
adipophilin; lipid-rich tumour; mammary analogue secretory carcinoma