Correlation of magnetic resonance imaging and pathologic size of infiltrating lobular carcinoma of the breast

BACKGROUND: Determining the extent of infiltrating lobular carcinoma (ILCA) in the breast is difficult. This study was designed to determine if the size of ILCA on magnetic resonance imaging (MRI) correlated with final pathology. METHODS: Retrospective study of patients between 1998 and 2004, who were evaluated for extent of ILCA prior to definitive treatment, was conducted. Demographic data and radiology and pathology results were obtained. Spearman correlation coefficient was used. RESULTS: Twenty-nine patients (median age 62 years) had MRI of breast. Fourteen patients (48%) had contralateral MRIs; 13 (45%) normal; 1 (8%) prompted core biopsy; 6 of 13 patients underwent contralateral mastectomies, which were benign. The distribution of tumor size was: T1 = 15 (52%); T2 = 7 (24%); T3 = 5 (17%); T4 = 2 (7%). Spearman correlation coefficient between tumor size on ultrasound and MRI with pathology was .19 (P = .5) and .88 (P < .001), respectively. CONCLUSION: MRI provided superior correlation between tumor size and pathology.