ESR1 and mucinous adenocarcinoma: ETV6 FISH can also be used to distinguish SBC from other disorders, including benign conditions such as juvenile papillomatosis with apocrine metaplasia or mucinous carcinoma, and microglandular adenosis or malignant lesions such as acinic cell carcinoma, cystic hypersecretory carcinoma, and apocrine carcinoma that have similar morphology and are ER, PR, and HER2-negative.