MASC is often strongly S100 positive and their defining feature is the presence of t(12; 15) (p13; q25) translocation that results in ETV6-NRTK3 gene fusion.4,5,7 ACC can occasionally undergo a high-grade transformation into an adenocarcinoma or undifferentiated carcinoma. This evidence concerns the gene ETV6 and undifferentiated carcinoma.