Diabetic Fibrous Mastopathy: Imaging Features With Histopathologic Correlation

Diabetic fibrous mastopathy (DFM) is a rare benign fibrotic disease of the breast that develops in patients with longstanding and often uncontrolled diabetes mellitus. Clinically, patients may present with an irregular, firm, palpable mass, which may be solitary or multiple, occurring in one or both breasts. Diabetic fibrous mastopathy occurs most often in premenopausal women with heterogeneously or extremely dense breasts; mammography may show focal asymmetry or, less often, a noncalcified mass with indistinct or obscured margins, but there are usually no discrete findings. On US, DFM may have marked hypoechogenicity and posterior shadowing secondary to extensive fibrosis. Diabetic fibrous mastopathy features on contrast-enhanced MRI are also nonspecific, with gradual persistent nonmass enhancement reported. Because the clinical presentation and US features of DFM overlap with those of breast cancer, histopathologic correlation is needed to confirm diagnosis and exclude malignancy. These findings include collagenous stroma often with keloidal features and chronic perilobular and perivascular inflammation. Histopathologic findings of lymphocytic lobulitis and perivascular inflammation are common to other autoimmune conditions.