Diabetic mastopathy is the occurrence of lymphocytic mastitis and stromal fibrosis in men as well as women having long-standing diabetes. Clinical and radiological appearance can raise a suspicion of malignancy and result in unnecessary biopsy. As these lesions are known to recur; failure to recognise them can have devastating results. A case of diabetic mastopathy is therefore presented for the knowledge and benefit of all so that unnecessary surgery can be avoided.