Breast duct widening is a symptom of breast duct widening when the width of the breast duct is found to be greater than 2mm during a mammogram. It is considered to be the cause of cystic hyperplasia of the breast. Due to the imbalance of estrogen and progesterone in the body’s hormone metabolism, the breast tissue overgrows and the breast ducts expand and the breast ducts widen. Most of them return to normal after menstruation and can be checked by ultrasound follow-up. The symptoms will be relieved significantly after lactation treatment. Ultrasound examination of plasmacytosis can also reveal dilated milk ducts, most of which are accompanied by local inflammatory infections and require symptomatic treatment. We cannot rule out that breast cancer is the cause of breast duct widening. If breast duct widening occurs, try to further examine the cause of the widening and then treat it symptomatically.