Mammary duct ectasia

**Definition:** A condition of the breast, caused by lipid and cellular debris or secretory (such as colostrum) stasis, or a nonspecific duct widening process. This condition is characterised by obstruction and subsequent dilation of the lactiferous duct, periductal inflammation, periductal fibrosis, nipple retraction, inversion, pain, or bloody discharge from the nipple.