Epithelial-myoepithelial carcinoma occurrence in the site of previously treated ductal carcinoma in situ of the breast: Imaging features with histopathologic correlation, a case report and review of the literature

IntroductionMultiple similarities in the embryogenic epithelial-myoepithelial cell differentiation of the salivary glands and breast tissue allows for overlap of neoplastic development of classically salivary gland tumors in the breast. While biphasic epithelial-myoepithelial lesions of the breast are uncommon and include pleomorphic adenoma, adenoid cystic carcinoma, and benign adenomyoepithelioma, malignant transformation of benign adenomyoepithelioma into epithelial-myoepithelial carcinoma of the breast is extremely rare, with fewer than 50 reported cases in the existing literature over the past four decades [1,2]. Thus far, there have previously been no cases that bring up the possibility of EMC development following the treatment of primary breast cancer in the existing literature.