Image Description
The differential diagnosis includes Mammary analogue secretory carcinoma (MASC) which has several overlapping histologic features with acinic cell carcinoma. Features supporting MASC include: absence of basophilic zymogen granules in the cytoplasm, presence of strong immunoreactivity for mammaglobin and S-100 protein, and the presence of t(12;15)(p13;q25) translocation resulting in ETV6-NTRK-3 gene fusion. The image shows acinar cells arranged in a microcystic pattern.