Medullary carcinoma of the breast: MRI findings.

Objective: The objective of our study was to describe the MRI findings of medullary carcinoma of the breast and to correlate those findings with the histopathologic findings.

Materials And Methods: From January 2005 to June 2010, MR images of 15 patients (age range, 32-73 years; mean age, 50 years) with pathologically confirmed medullary carcinoma of the breast were retrospectively evaluated according to BI-RADS. MR images were reviewed for the following: enhancement type (mass vs nonmass), size, shape, margins, contrast enhancement, signal intensity, and time-intensity curve pattern on a dynamic study. These MR features were correlated with the histopathologic features.

Results: All 15 tumors were seen as a mass on MRI. The median size of the masses was 2.7 cm (range, 1.5-6.3 cm) and the most common features were an oval or lobular shape (13/15, 86.7%) and a circumscribed margin (13/15, 86.7%). Rim enhancement with enhancing internal septations was seen in seven masses (46.7%), and rim enhancement was seen in six masses (40%). A hypointense rim on T2-weighted images was seen in nine tumors (9/15, 60%). Last, the kinetics curve showed a rapid initial increase in enhancement and a washout or plateau pattern on delayed phase imaging in all 15 tumors.

Conclusion: On MRI, medullary carcinomas of the breast appeared as masses with an oval or lobular shape and circumscribed margins. Rim enhancement with or without enhancing internal septations was frequently seen on contrast enhancement.