Abstract
A 79–year–old postmenopausal woman was seen for a hard mass 5.0 cm in diameter resembling breast cancer in the upper outer left–breast quadrant. Mammography showed asymmetrical density and ultrasonography revealed an irregular hypoechoic lesion with posterior acoustical shadowing. Contrast–enhanced computed tomography (CT) detected no focal enhanced lesion in the thickened left breast, but contrast–enhanced magnetic resenance imaging (MRI) showed gradual patchy lesion enhancement. Despite the initial breast cancer diagnosis, we found imaging inconsistent with typical breast cancer. The woman had been treated for Type 2 diabetes mellitus for 45 years, so her clinical history and the inconsistency yielded a final diagnosis of diabetic mastopathy. This was confirmed histologically following incisional biopsy. Diabetic mastopathy may be difficult to distinguish from breast cancer, but can be correctly diagnosed before surgical biopsy through accurate medical examination, interview, and imaging diagnosis.
