Diabetic mastopathy (DMP) is a breast-related complication of type 1 or type 2 insulin-dependent diabetes mellitus (IDDM). It manifests as hard, fibrous, and painless masses in one breast or both breasts. These masses are benign and irregular in shape. Interestingly, this condition is also seen in men.
Clinical findings in DMP are mostly inconclusive. The masses seen in DMP are large and painless and not easily distinguishable from those seen in breast carcinomas. It is commonly present in both breasts, especially during end stage of disease. It is also usually accompanied by other complications of chronic diabetes mellitus. Identifying this condition precisely and differentiating it from carcinoma is critical for avoiding unnecessary surgical procedures.
Pathologists need to be very careful during diagnosis of DMP as it is easy to misdiagnose and it can recur after some time. As DMP masses look similar to those in breast carcinoma, pathologists and radiologists should be able to differentiate between the two. A correct diagnosis can save patients from unwanted surgical biopsies. No evidence exists to suggest that DMP leads to breast cancer or stromal neoplastic diseases.
Symptoms of DMP vary largely in terms of intensity from one person to another. Symptoms usually occur shortly before the beginning of a menstrual cycle or during the premenstrual syndrome.
The most common symptoms of DMP include the following:
DMP is a form of stromal fibrosis and lymphocytic mastitis. Fibrosis and infiltrate containing predominantly B-cell lymphocytes are seen around the ducts, vessels, and lobules.
The exact pathogenesis of DMP is not fully understood yet and there are likely multiple factors in play that cause an immunological reaction. DMP is treated as a type of lymphocytic mastitis and is included in the category of other immunologic breast conditions such as Sjogren's syndrome, systemic lupus erythematosus, and Hashimoto thyroiditis.
The precise cause behind DMP is still unknown. The condition is considered to be a type of auto-immune reaction. Some theories propose that exogenous insulin can cause an inflammatory or immunologic reaction which can lead to the development of tumors seen in DMP.
They can also be a result of the expansion of extra cellular matrix as a result of increase in production and decrease in degradation of collagen. This happens in the connective tissues sometimes due to hyperglycemia.
DMP has been found to be more common in type I diabetes mellitus than in type II diabetes mellitus. Some studies report that certain features of DMP are similar to that of autoimmune diseases such as thyroiditis. Despite many published reports on this condition in pathology, and radiology-related literature, DMP is poorly diagnosed because routine breast examinations are rare in young diabetic patients.
Both imaging and physical examinations fail to provide clear cut evidence that can distinguish DMP from breast cancer. In some cases with a strong clinical history and high possibility of DMP, a core biopsy guided by an ultrasound was shown to help in initial diagnosis.