Mammary analogue secretory carcinoma: update on a new diagnosis of salivary gland malignancy

Abstract

Objectives/hypothesis: To review the known histopathologic findings and clinical behavior of mammary analogue secretory carcinoma (MASC).

Data sources: PubMed.

Review methods: Literature search using the terms "Mammary analogue secretory carcinoma," "Mammary analog secretory carcinoma," and "MASC" to identify all relevant publications.

Results: MASC is an unusual and rare malignant salivary gland tumor first described in 2010. It shares histologic, immunohistochemical, and genetic features with secretory carcinoma of the breast. The clinical behavior of MASC ranges from slowly growing tumors that infrequently recur after surgical resection to aggressive tumors that cause widespread metastasis and death. Many cases of MASC were discovered in archived cases previously classified as acinic cell carcinoma, mucoepidermoid carcinoma, and adenocarcinoma not otherwise specified.

Conclusion: MASC is a newly recognized variant of salivary gland malignancy. Further research is needed to better delineate its overall prevalence and to define an appropriate treatment algorithm for this new clinical entity.

Keywords: Salivary gland carcinoma; head and neck surgery; mammary analogue secretory carcinoma; parotid malignancy.

FIGURE 1. Magnetic resonance image (MRI) axial images

A) T1 sequence pre-Gadolinium demonstrates a well-circumscribed right parotid lesion hyperintense relative to muscle B) T1 sequence post-Gadolinium demonstrates partial enhancement C) T2 sequence demonstrates hyperintensity relative to parotid gland.

FIGURE 2. Fine needle aspirate

A-B) Papanicolaou stained ThinPrep slide showing tumor cells with crowding, enlarged nuclei with promiment nucleoli, and cytoplasmic vacuolization C) Hematoxylin and eosin stained cell block preparation showing cells with vacuolization of the eosinophilic cytoplasm and a microcystic architecture.

FIGURE 3. Gross and histologic pathology of the tumor

A) Gross appearance is that of a well-circumscribed partially cystic tumor B-C) Low-powered view demonstrates solid, microcystic and pseudopapillary architectural patterns with abundant eosinophilic, colloid-like secretions D) High-powered view reveals tumor cells with eosinophilic finely granular to vacuolated cytoplasm and round to oval nuclei with prominent nucleoli. (B-D, Hematoxylin and Eosin stains).