Diabetic mastopathy is a rare fibro-inflammatory breast disease, which occurs in premenopausal women affected by longstanding type I insulin-dependent diabetes. It is a benign disease and it is often misunderstood for its clinical and radiological features that may mimic a breast cancer. The diagnosis of diabetic mastopathy is based on histological examination and it is characterized by lymphocytic lobulitis with glandular atrophy and perivascular lymphocytic infiltration. The patients do not need to undergo surgery but it is necessary to plan an adequate clinical and radiological monitoring program.