Photo Essay -
Secretory Carcinoma of Salivary Glands (MASC):
A recently described Salivary Gland Tumour -
Mammary Analogue Secretory Carcinoma of Salivary Glands (MASC):
This tumor shares histologic features, immunohistochemical profile, and a highly specific genetic translocation, ETV6-NTRK3, with secretory carcinoma of breast.
Secretary Carcinoma of the breast
Histologically, it is often mistaken as acinic cell carcinoma, adenocarcinoma not otherwise specified, and other primary salivary gland tumours.
a) The tumour is well circumscribed and surrounded by a thick, not interrupted fibrous capsule ;
b) Microcystic and slightly dilated glandular spaces filled with an eosinophilic homogenous secretory material ;
c) Minor component is represented by papillary structures ;
d) A macrocystic growth pattern ;
e) cystic structures lined mostly by a single and, focally, a double layer of cells with focal apocrine differentiation ;
f ) cells with abundant pale pink vacuolated and foamy cytoplasm and vesicular, bland looking nuclei with prominent nucleoli ;
Majewska H, Skálová A, Stodulski D, et al. Mammary analogue secretory carcinoma of salivary glands: a new entity associated with ETV6 gene rearrangement. Virchows Archiv. 2015;466(3):245-254. doi:10.1007/s00428-014-1701-8. (This article is distributed under the terms of the Creative Commons Attribution License)
Mammary analogue secretory carcinoma of salivary glands (MASC) was first described by Skálová et al. in 2010.
This rare salivary gland tumour is characterized by the ETV6-NTRK3 fusion gene.
It is usually seen in men and predominantly involves parotid gland. Mammary analogue secretory carcinoma can occur in other locations like lips.
More image: Macroscopic and histological morphology of mammary analogue secretory carcinoma. The cut section of the tumor was uncircumscribed and whitish, invading into the connective tissue surrounding the parotid gland
Microscopically, this low grade tumour has a lobulated appearance and displays microcystic, cystic-papillary, glandular, and solid patterns. The glandular spaces contain abundant eosinophilic homogenous or bubbly secretory material positive for periodic acid-Schiff, mucicarmine, MUC1, MUC4, and mammaglobin. The neoplastic cells have pale, ovoid nuclei with minimal pleomorphism, the cytoplasm is vacuolated or eosinophilic. Image1 ; Image2 ; Image3 ; Image4
Intraluminal and intracytoplasmic PAS-D positive secretion
Serrano-Arévalo ML, Mosqueda-Taylor A, Domínguez-Malagón H, Michal M. Mammary Analogue Secretory Carcinoma (MASC) of salivary gland in four Mexican patients. Medicina Oral, Patología Oral y Cirugía Bucal. 2015;20(1):e23-e29. doi:10.4317/medoral.19874. (This is an open-access article distributed under the terms of the Creative Commons Attribution License)
Cytomorphology of mammary analogue secretory carcinoma.
The cytological distinction between zymogen granule-poor Acinic cell carcinoma and MASC without molecular study or immunohistochemical study is very difficult, since the cytology of MASC has many overlapping features with Acinic cell carcinoma. However, there are several cytological features suggestive of MASC, such as papillary structure, extracellular and intracellular mucinous material, vacuolated cytoplasm, tumour cells with low-grade nuclear atypia, and abundant vascularity.
The tumor cells are strongly positive for S100 protein, STAT5a and mammaglobin and negative for DOG-1. STAT5a shows strong nuclear expression in tumor cells. Mammaglobin in all cases stains cytoplasm.
Perineural invasion is rare and lymphovascular invasion has not been reported. MASC is currently regarded as a low-grade carcinoma.
MASC has a higher risk for regional lymph node involvement than acinic cell carcinoma.
Image Lymph node metastasis of MASC.
Mammary analogue secretory carcinoma of salivary glands may follow an aggressive behavior or transform into a high grade neoplasm. Skalova reported cases with conventional MASC and a population of anaplastic cells with perineural invasion.
Mammary analogue secretory carcinoma of salivary glands, containing the ETV6-NTRK3 fusion gene: a hitherto undescribed salivary gland tumor entity.
Serrano-Arévalo ML, Mosqueda-Taylor A, Domínguez-Malagón H, Michal M. Mammary Analogue Secretory Carcinoma (MASC) of salivary gland in four Mexican patients. Medicina Oral, Patología Oral y Cirugía Bucal. 2015;20(1):e23-e29. doi:10.4317/medoral.19874.
Mammary Analogue Secretory Carcinoma of Salivary Gland Origin: An Update and Expanded Morphologic and Immunohistochemical Spectrum of Recently Described Entity.
Majewska H, Skálová A, Stodulski D, et al. Mammary analogue secretory carcinoma of salivary glands: a new entity associated with ETV6 gene rearrangement. Virchows Archiv. 2015;466(3):245-254. doi:10.1007/s00428-014-1701-8.
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