In recent years, the number of patients with plasmacytoid mastitis has been increasing clinically. The initial appearance of the breast lump is very similar to breast cancer, and the lump softens to form an abscess, which easily forms a fistula after ulceration and does not heal easily or repeatedly ulcerates, causing great suffering to the patient. Plasmacytoid mastitis is a disease of the breast ducts that is called inflammation but is not a bacterial infection. Its clinical manifestations can be broadly divided into three stages. 1. Overflow phase: Nipple discharge is an early manifestation of plasmacytoid mastitis, which is intermittent, spontaneous and can last for a long time. Patients or physicians often overlook small, intermittent amounts of nipple discharge. Some patients have complete or incomplete nipple depression, which is congenital in a significant proportion of patients and occurs gradually in some patients after the onset of the disease. 2.Lumpy stage: It often starts suddenly and develops rapidly. The patient feels localized pain and discomfort in the breast, which can be tingling or vague, and a lump is found. The lumps are mostly located under the areola or extend in a certain direction. The lumps are of different sizes and irregular shapes, with a hard and tough texture and a nodular surface with poorly defined borders. The lump may be locally red, swollen, and hot, with significant pain, and the redness may extend to 1/4 – 1/2 of the breast. The skin of the breast may be edematous, and some may have orange peel-like changes. Some patients may have a breast lump that is predominantly enlarged for 3 years, 5 years, or longer, but without significant erythema. 3, fistula stage: later breast lumps softened, forming abscesses, the pus flowing out after the rupture is often interspersed with acne-like material or grease-like material. The fistula is often formed leading to the milk hole, the wound does not converge for a long time or repeatedly ulcerated, the local tissue is hard and uneven, the nipple is more depressed. Fistulas can be simple or complex. The fistula is mostly located in the areola, but also in the breast, but is ultimately connected to the nipple orifice. The disease can occur in women of any age after puberty and all develop during the non-lactating period. Most patients have congenital total or partial nipple depression. Unilateral onset is common, but there are also cases of bilateral breast onset. The onset of the disease is slow and can last for several months or years. The diagnosis of this disease can be made based on the following aspects (1) The onset of the disease is not during lactation or pregnancy; (2) Most patients have congenital total or partial nipple depression; (3) The breast lump is initially located in the areola, and the lump may be locally red and swollen when suppurating but the systemic inflammatory response is atypical; (4) The abscess is often mixed with powder-like material in the pus after ulceration, and the wound is recurrent and forms a fistula leading to the nipple; (5) Mammography, needle aspiration cytology of the lump, and other ancillary examinations help to clarify the diagnosis. (5) mammography, lump needle aspiration cytology, and other ancillary tests can help clarify the diagnosis. In the treatment of plasmacytoid mastitis, Western medicine mainly adopts surgical treatment, depending on the condition, using ductal resection, segmental mastectomy, and simple mastectomy, respectively. In severe cases of plasmacytoid mastitis, partial mastectomy is often not the answer and simple mastectomy is the only option. The treatment of this disease with Chinese medicine is very characteristic, especially the external treatment method of Chinese medicine is outstanding in the treatment of this disease, with the Chinese medicine dialectical treatment, the efficacy is better, rarely need to do simple mastectomy.