Role of breast magnetic resonance imaging in predicting residual lobular carcinoma in situ after initial excision.

BACKGROUND: Breast magnetic resonance (MR) imaging is a useful screening modality in detecting suspicious lesions in patients with a history of lobular carcinoma in situ (LCIS). This study aimed to evaluate the effectiveness of breast MR imaging in detecting remnant LCIS lesions after initial excision.

METHODS: Between 2011 and 2015, 29 patients with LCIS who underwent initial excision were enrolled. Breast ultrasonography and breast MR imaging was conducted after initial excision. Imaging findings were compared with pathologic results.

RESULTS: There were nine (31.0%) cases with positive margins after initial excision; they were LCIS (n=8) and atypical lobular hyperplasia (n=1). Residual lesions were identified in 12 cases; they were invasive lobular carcinoma (n=1; 3.4%), LCIS (n=9; 31.0%), atypical lobular hyperplasia (n=1; 3.4%), and papillary carcinoma in situ (n=1; 3.4%). Prior to the second operation, these lesions could be detected in seven cases using ultrasonography (sensitivity, 53.3%; specificity, 100%) and in 10 cases using breast MR imaging (sensitivity, 83.3%; specificity, 100%).

CONCLUSIONS: Breast MR imaging showed higher sensitivity than breast ultrasonography in detecting remnant LCIS lesions. If a suspicious lesion was found using breast MR imaging, a second operation should be considered because of the possibility of multifocality, even if LCIS was confirmed at the initial operation.