Adenomyoepithelioma of the Breast: Radiologic-Pathologic Correlation and Management

Adenomyoepithelioma (AME) is a rare, usually benign breast neoplasm with low potential for malignant transformation. Imaging features are nonspecific and overlap with other benign and malignant breast lesions. On mammography, AME most often presents as a mass, usually oval in shape, with variable reported margins. Less commonly, AME can present mammographically as an asymmetry or can be mammographically occult. Associated calcifications are uncommon. On US, AME is usually seen as a hypoechoic oval mass, but it can also manifest as a complex cystic and solid mass. On US, the majority of AME have noncircumscribed margins (indistinct, angular, or microlobulated). Internal vascularity is usually present, and posterior enhancement can be seen. Although there is limited literature on MRI features, the most frequent finding is an irregular mass with washout kinetics; T2 hyperintensity can be observed. These nonspecific and often suspicious imaging features usually merit biopsy. On histologic analysis, AME is characterized by a biphasic proliferation of myoepithelial and epithelial cells. Pathologic diagnosis can be difficult due to the variety of histologic features of AME and heterogeneity in these tumors, especially when sampling is limited, such as in core needle biopsies. Wide local surgical excision of AME is recommended due to potential for recurrence and malignant transformation.