A case of diabetic mastopathy with multiple lesions mimicking breast cancer.

We report a case of diabetic mastopathy with multiple unilateral lesions in an insulin dependent patient. The patient was a 62-year-old woman with two hard tumors in the right breast, who had been treated with insulin for diabetes mellitus. Mammography revealed a highly dense tumor in the right breast, while ultrasonography showed two irregular hypoechoic lesions with marked posterior acoustical shadowing, suggesting scirrhous carcinoma. On magnetic resonance imaging the two lesions had slightly heterogeneous enhancement. Aspiration breast cytology showed insufficient cellular material for evaluation. Excisional biopsy was performed because the patient wanted confirmation and treatment. Fibrosis with dense lymphocytic infiltration around the lobules and ducts was diagnosed histopathologically. These findings were compatible with diabetic fibrous mastopathy. Although this disease is thought to be a diabetes-induced reaction of autoimmune origin, multiple lesions are rare. This is the first case of unilateral multiple lesions of diabetic mastopathy.