Mammary analogue secretory carcinoma of salivary glands, containing the ETV6-NTRK3 fusion gene: a hitherto undescribed salivary gland tumor entity
Abstract
We present series of 16 salivary gland tumors with features reminiscent of secretory carcinoma of breast. This is hitherto undescribed salivary gland neoplasm, with features of both acinic cell carcinoma (AciCC) and low-grade cystadenocarcinoma.
Microscopically, tumors are composed of microcystic spaces with secretory material positive for PAS, mucicarmine, MUC1, MUC4, and mammaglobin. The neoplasms show vimentin, S-100, and STAT5a positivity.
For this tumor, we propose term mammary analogue secretory carcinoma of salivary glands (MASC). 16 patients comprised 9 men and 7 women, mean age 46 years. 13 cases occurred in parotid, and one each in minor salivary glands of cheek, lip, and palate. Mean tumor size was 2.1 cm.
Four patients suffered local recurrences, two patients died. We have shown t(12; 15) (p13;q25) ETV6-NTRK3 translocation in all but one case of MASC suitable for analysis.
Thus, our results strongly support concept that MASC and AciCC are different entities.