MR imaging of the breast in patients with invasive lobular carcinoma

dOBJECTIVE. Our objective was to assess the usefulness of MR imaging in pat ients diagnosed with invasive lobular carcinoma of the breast. MATERIALS AND METHODS. Between July 1993 and September 1999, 32 women (33 c ases) diagnosed with pure invasive lobular carcinoma of the breast underwen t contrast-enhanced MR imaging examination, One woman was excluded because of lack of follow-up. Correlation was made between the mammographic and son ographic findings, the MR imaging findings, and the final pathology results for the remaining 32 cases. RESULTS. in 18 women who did not undergo excisional biopsy before the MR im aging, MR imaging showed more extensive tumor burden or the detection of th e primary lesion that was occult on conventional imaging in seven (38.9%) o f 18 women, in nine (50%) of 18 women, MR imaging performed equally as well as mammography and sonography. In one case (5.6%), MR imaging and mammogra phy underestimated disease extent. In another patient (5.6%), MR imaging ov erestimated tumor burden, although mammography failed to show the cancer. I n 14 patients who had excisional biopsy before the MR imaging, residual tum or was shown in eight women (57.1%) with extensive tumor or additional sepa rate foci in five of the eight patients. In two cases (14.3%) that were int erpreted as equivocal, residual tumor was shown in both cases on reexcision , In three cases (21.4%), the MR imaging was interpreted as negative, but m icroscopic tumor was shown around seroma on reexcision. False-positive enha ncement was seen in one case (7.1%), CONCLUSION. MR imaging showed more extensive tumor than conventional imagin g and affected the clinical management in 16 (50%) of 32 patients with inva sive lobular carcinoma.