Ductal dilatation can be caused by factors such as plasmacytoid mastitis, mastopexy, and papilloma in the milk ducts. Due to localized poor patency and localized obstruction of the breast ducts, localized dilatation of the breast ducts will appear during ultrasound examination in the hospital, which is described by ultrasound. Due to degenerative diseases and autoimmune diseases in middle-aged and elderly people, nipple depression and deformity may occur. The squamous epithelium of the breast penetrates deep into the inner wall of the ducts, forming local obstruction, and secretions in the ducts stimulate the walls of the ducts to form inflammation, and local duct dilatation may occur during this examination. Mammary gland hyperplasia is also a factor that causes ductal dilatation, mainly due to changes in hormone levels before menstruation and local lump growth. If the ducts of the breast are compressed, it will affect the ducts of the breast that cannot secrete mucus and cause obstruction causing dilation. Papillomas in the milk ducts can cause dilation of the milk ducts due to over-stimulation by estrogen, which leads to restricted papillary growths in the milk ducts.