Background: Conventional imaging with mammography and ultrasonography has a low sensitivity for diagnosis and a tendency to underestimate the extent of invasive lobular carcinoma (ILC) of the breast. The aim was to determine whether magnetic resonance imaging (MRI) had any advantages for the characterization of ILC.
Methods: Twenty patients with histologically proven ILC underwent preoperative imaging with MRI. MRI was performed to aid detection of malignancy in six patients with a clinically suspicious presentation but normal or indeterminate imaging on mammography and ultrasonography. In 14 patients MRI was performed to determine tumour extent.
Results: MRI accurately identified malignancy in five of six patients with normal or indeterminate conventional imaging. In seven of 14 patients in whom MRI was performed to determine tumour extent, it provided significant additional information. These included four patients in whom conventional imaging grossly underestimated tumour size, two patients in whom MRI identified an unsuspected contralateral breast tumour and one patient in whom MRI predicted tumour invasion of the pectoral muscle. The correlation between tumour size on histological examination was better with MRI (r = 0.967) than with mammography (r = 0.663) and ultrasonography (r = 0.673).
Conclusion: MRI can provide considerable additional information in the detection and characterization of ILC.