Plasmacytoid mastitis is a complex inflammatory disease of the breast, so named because of the large number of plasma cells infiltrating the tissue surrounding the inflammation. In addition, it has many different names, the most common being “ductal dilatation syndrome”, “occlusive mastitis”, “non-lactating mastitis” and “Chronic mastitis”, etc. The disease is caused by irregular hyperplasia of the epithelium of the breast ducts, secretion dysfunction, and accumulation of lipid secretions in the large milk ducts under the nipples and areola, causing dilation of the milk ducts, and later decomposition of the accumulation, resulting in chemicals that constantly stimulate the surrounding tissues and cause inflammation. Sometimes the inflammation can become acute and become an abscess, so the pus is often laced with bean curd-like or powder-like material, so it is also called “pimple mastitis” and “pimple canker sore” in Chinese medicine. Many people do not recognize this disease and mistake it for a common bacterial infection, or misdiagnose it as breast tuberculosis, or worst of all, misdiagnose it as breast cancer and cut the breast. Plasmacytoid mastitis occurs in association with nipple dysplasia, like nipple inversion, nipple splitting, etc. The inwardly turned nipple becomes a hiding place for dirt, often with pimple-like things, and sometimes with a bad smell. Nipple deformities also inevitably cause distortion and deformation of the ducts. The ducts are then easily blocked, and the duct contents are lipidic substances that leach the duct walls causing overflow, causing chemical inflammation, and a large number of lymphocytes and plasma cells react to form small inflammatory masses. The lesions are mostly near the areola and are locally red, swollen and painful. Usually there is no fever. After a few days it can subside on its own, and when the resistance is low due to exertion, cold, etc., it attacks again, but once more than once, the mass gradually becomes larger and red, and generally the doctor considers it to be a small abscess, or uses antibacterial injections and infusions, and finally incises and drains it, so that a fistula is formed, which is difficult to heal. Sometimes the redness breaks down on its own and again does not heal for a long time. The lesions can also occur in multiple places, forming multiple fistulas and even interconnecting with each other, leaving the breast full of holes. This is very similar to breast tuberculosis. If the lump is far from the nipple and adheres to the skin, it is very much like breast cancer. Therefore, we should understand pulpy breast, not to delay the diagnosis, and strive for a one-time cure. Clinical features: 1. Not related to pregnancy and breastfeeding, i.e. not occurring during breastfeeding. 2. Most patients have various deformities of the nipple or dilated ducts. 3. There are many young women and many unmarried ones. 4. Recurrent, long-lasting parareolar fistulas or chronic inflammatory masses. There is a case with a history of up to 13 years. 5, This disease is not uncommon, accounting for about 10% of breast patients. Traditional Chinese medicine treatment for this disease takes auricular acupuncture point blood compress, local cupping and other methods, with other methods to achieve good results.