Invasive micropapillary carcinoma of the breast: clinical, mammographic, and sonographic findings with histopathologic correlation.

OBJECTIVE: The purpose of our study was to investigate the imaging features of invasive micropapillary carcinoma of the breast, which is a recently described, rare variant of infiltrating ductal carcinoma.
CONCLUSION: Invasive micropapillary carcinoma of the breast usually manifests as a firm, immobile mass. Findings on mammography are of a spiculated, irregular or round, high density mass with or without associated microcalcifications. On sonography, the common findings are of a homogeneously hypoechoic, irregular or microlobulated mass with posterior acoustic shadowing or normal sound transmission. Axillary lymph nodes are frequently involved. Although these findings are not specific and may be seen with other breast malignancies, invasive micropapillary carcinoma should be included in the differential diagnosis for breast masses with these imaging features. Also, radiologic findings may help in the histopathologic differentiation of cases that are difficult to diagnose, such as metastatic tumors.