Mammary Duct Ectasia

Mammary duct ectasia (MDE) is a non-proliferative inflammatory disorder of the large duct (milk duct) of the breast; as such, it affects the nipple and areola complex. In MDE, focal dilatation of the lactiferous duct system is due to endoluminal changes, as well as the loss of duct wall elastin, leading to abnormally dilated and tortuous lactiferous ducts with associated periductal inflammation and fibrosis. The patient commonly presents with intermittent nipple discharge of varying colors (ranging from white to green/black to grey), as well as pain and tenderness of the nipple and areola. Other symptoms can include an inverted nipple or a palpable breast "lump," though, in many instances, MDE is asymptomatic. MDE can mimic more serious conditions, such as breast malignancy, or other benign processes, such as mastitis. The clinical manifestations of mammary duct ectasia overlap with another benign inflammatory condition known as periductal mastitis, a condition that occurs at the nipple-areola complex (more commonly in smokers), and sometimes the two conditions cannot be distinguished from each other on clinical assessment, with the final diagnosis possible only after histopathologic examination of the excised duct tissue with the affected surrounding tissue.