"Diabetic mastopathy," or sclerosing lymphocytic lobulitis, is strongly associated with type 1 diabetes.

OBJECTIVE To demonstrate the strong association of diabetic mastopathy or sclerosing lymphocytic lobulitis with type 1 diabetes mellitus by studying appropriate control groups and to describe risk factors and natural history of the disorder. RESEARCH DESIGN AND METHODS This was a retrospective cross-sectional study of four groups of patients conducted at a setting tertiary care medical center. We examined benign breast biopsies (investigator masked to identity) from age-matched patients with types 1 and 2 diabetes, autoimmune thyroid disease, or none of the above disorders for sclerosing lymphocytic lobulitis. Several risk factors proposed for the disorder (age at diagnosis of benign breast disease, duration of diabetes, age at onset of diabetes, prevalence of retinopathy, neuropathy, nephropathy and cheiroarthropathy, glycemic control, parity, oral contraceptive use, menopausal status, or number of breast biopsies) were evaluated, and patients were contacted to describe the natural history of the disorder. RESULTS Sclerosing lymphocytic lobulitis was identified in 69.7% of the subjects with type 1 diabetes and 1.8% of those with autoimmune thyroid disease diagnosed with benign breast disease at surgery. It did not occur in patients with type 2 diabetes with or without insulin treatment or in control subjects. Only retinopathy and peripheral neuropathy were associated with sclerosing lymphocytic lobulitis. Breast carcinoma or lymphoma did not occur subsequently in any type 1 diabetes patient with or without sclerosing lymphocytic lobulitis. CONCLUSIONS Sclerosing lymphocytic lobulitis is strongly associated with type 1 diabetes. Retinopathy and neuropathy are associated with the disorder. The risk of malignancy is not increased.