Searching for mammary analog secretory carcinoma of salivary gland among its mimics

Abstract

Mammary analog secretory carcinoma of salivary gland is a recently described entity with unique morphologic, clinical, and genetic characteristics, including the characteristic t(12;15)(p13;q25) with ETV6-NTRK3 translocation found in secretory carcinomas of the breast. Before their initial description, these salivary gland tumors were generally diagnosed as acinic cell carcinoma or adenocarcinoma. For the purpose of this study, all cases of salivary gland acinic cell carcinoma, cribriform cystadenocarcinoma, and adenocarcinoma, not otherwise specified (NOS), diagnosed over a 10-year period were retrieved from our surgical pathology files. There were a total of 11 cases diagnosed as acinic cell carcinoma, 10 cases of adenocarcinoma, NOS, and 6 cases of cribriform cystadenocarcinoma. All slides were reviewed by two pathologists (AP, CGF) and tumors that show morphologic features of mammary analog secretory carcinoma according to the recent literature were selected. This process narrowed down the initial number to six cases originally diagnosed as acinic cell carcinoma, three cases originally diagnosed as adenocarcinoma, NOS, and one case originally diagnosed as cribriform cystadenocarcinoma. The 10 cases were subjected to immunohistochemistry for S-100, mammaglobin, and ANO1, as well as fluorescence in situ hybridization analysis for t(12;15)(p13;q25) with ETV6-NTRK3 fusion rearrangement. The ETV6-NTRK3 gene rearrangement was detected in three tumors. These three tumors, initially diagnosed as acinic cell carcinomas, stained positive for S-100 and mammaglobin, and negative for ANO1 by immunohistochemistry. Two of the three patients were male (2/3). In summary, mammary analog secretory carcinoma is a newly described diagnostic entity that should be in the differential diagnosis of salivary gland tumors that morphologically mimic other neoplasms, mainly acinic cell carcinomas. They differ from conventional acinic cell tumors immunohistochemically and molecularly. Positivity for mammaglobin and S-100, and negativity for ANO1 are useful screening tools before confirmatory molecular studies.

An FNA pitfall: Mammary analog secretory carcinoma mistaken for acinic cell carcinoma due to cytoplasmic granules

“…One cytology report of MASC considered ACC or a myoepithelial neoplasm [9] due to single or clustered cells with low grade nuclei and prominent nucleoli and signet ring and plasmacytoid cells. If feasible, immunostains positive for S100 and mammoglobin and negative for DOG1 would favor MASC [10,11]. However, to date, only ETV6 rearrangement stands as the defining diagnostic criterion.…”

Expression of SOX10 in Salivary Gland Oncocytic Neoplasms: A Review and a Comparative Analysis with Other Immunohistochemical Markers

“…In this context, SOX10 is similar to DOG1 in ruling out benign lesions such as WT and ONC. However, as with DOG1, negative SOX10 results do not favor a benign diagnosis since MEC is often negative for both markers [12,16,22]. …”

The cytopathologic features of mammary analog secretory carcinoma and its mimics

“…was published,[1] many authors have begun to catalog the diagnosis and clinicopathologic characteristics of mammary analogue secretory carcinoma (MASC). However, while the literature concerning the histological characteristics of MASC is burgeoning,[2345] the cytomorphological features of MASC and its addition to the differential diagnosis of a salivary gland fine-needle aspiration (FNA) specimen by cytopathologists is just emerging. Until date, few cases of MASC sampled by FNA have been reported;[678910] with one lesion diagnosed via cytological analysis (the remaining cases received a final diagnosis of MASC after histological evaluation).…”