Mammographic Appearances of Breast Medullary Carcinoma: Comparison with Pathology and Differentiation with Fibroadenoma

Objective To evaluate mammography in distinguishing medullary carcinoma from fibroadenoma and in distinguishing true from atypical medullary carcinoma.Materials and Methods Mammographic findings of 27 medullary carcinomas and 34 fibroadenomas were retrospectively analyzed. The findings were compared with pathologic results.Results The most common finding was non-calcified mass for both medullary carcinoma (78%) and fibroadenoma (74%). Usually, the mass was of high-density for medullary carcinoma (19/25) and of iso-density for fibroadenoma (19/28), with significant difference between two tumors (P=0.001). Most medullary carcinomas showed an infiltrating or lobulated border (23/25), while most fibroadenomas had a clear border or could be demonstrated only on a certain direction exposure (25/28), with significant difference between two tumors (P0.001). Of 27 medullary carcinomas, 9 were atypical. No obvious difference in tumor's shape (P=0.670), margin (P=0.394) and density (P=0.637) existed between the true and the atypical medullary carcinomas. Conclusion Breast medullary carcinoma has certain mammographic features, which are well correlated with its pathology and based on which differentiation from fibroadenoma can be made. Pathologically, medullary carcinoma can be further divided into true type and atypical type. Nevertheless, it is almost impossible to make a correct differentiation of the two types on the mammogram.