Non mass-like enhancement categories detected by breast MRI and histological findings.

OBJECTIVE To correlate the different non masslike enhancement categories detected by Magnetic Resonance Imaging (MRI) and the corresponding histological findings. PATIENTS AND METHODS Two experienced radiologists reviewed the MRI examinations of 94 patients presenting non mass-like enhancements who had performed histological evaluation. According to the BI-RADS (Breast Imaging Reporting and Data System) lexicon, non masslike enhancements were classified as focal, linear, segmental, regional, ductal and diffuse enhancements. We focused on segmental, regional and ductal patterns. RESULTS Among the 94 patients, 52.1% showed a regional pattern, 27.7% a segmental pattern and 20.2% a ductal pattern of enhancement. Of the 49 patients showing a regional pattern, the histological diagnosis was ductal invasive carcinoma (DIC) in 28 cases, ductal carcinoma in situ (DCIS) in 4 cases, lobular invasive carcinoma (LIC) in 3 cases and a benign disease in 9 cases. Of the 26 patients showing a segmental pattern, the histological outcome was DIC in 10 cases, DCIS in 7 cases and a benign disease in 5 cases. Among the 19 patients showing a ductal pattern, the result was DIC in 4 cases, DCIS in 4 cases and a benign disease in 7 cases. In most cases DIC presented as a regional pattern, while DCIS showed a segmental pattern in 26.9%, a ductal pattern in 21.1% and a regional pattern in 8.2% of cases. CONCLUSIONS Our findings about ductal and segmental enhancements agree with the literature. We found a high rate of DIC presenting as a regional enhancement, instead; thus, we recommend a more detailed diagnosis, especially when an homogeneous/heterogeneous and clumped internal enhancement pattern is present.