Plasmacytoid mastitis occurs mostly in non-lactating, young or even unmarried women, mostly with nipple dysplasia or nipple deformities, such as nipple entropion, split nipples, and flat nipples. The initial localized redness, swelling and pain next to the areola, recurrent and long-lasting, rupture or incision, followed by bacterial infection, forming a fistula, which is difficult to heal, and pathology shows a large number of plasma cell infiltrates around the lesion, which is one of the important features of the disease. Plasmacytoid mastitis, also known as “ductal dilatation”, “acne mastitis”, “occlusive mastitis”, etc., has a complex and variable clinical presentation, with redness, swelling and pain in the acute phase, and nipple discharge in the chronic phase. The clinical manifestations are complex and variable, with redness, swelling and pain in the acute stage, nipple overflow, invagination deformity and breast lumps in the chronic stage, which can easily be misdiagnosed as bacterial mastitis and breast cancer. Plasmacytoid mastitis presents clinically as nipple discharge, which is often yellowish plasma, but can also be cloudy, creamy, bloody or purulent green or brown fluid. It may be accompanied by slight pain in the breast; inflammatory manifestations of varying degrees of local redness, swelling, heat, pain and systemic reactions in the breast; breast masses of varying sizes, appearing as mixed masses with indistinct borders and hard texture. Most breast abscesses have a chronic course, with smaller masses around the areola and larger masses in the periphery. When the abscess is incised or self-ruptured, the wound does not heal for a long time or recurs soon after temporary healing, forming single or multiple fistulas or sinus tracts, which can continue for several years without healing. Ductal dilatation of nipple overflow can be done by ductal irrigation of the breast. Chinese medicine is used to cool the blood, clear heat and detoxify the body. If an abscess forms, it should be incised promptly and the diseased duct should be removed; if a sinus fistula has formed, sinus and fistula excision can be done. If the inflammation extensively affects the whole or most of the breast and the skin has been severely adhered to form more fistulas, a simple mastectomy or subcutaneous simple mastectomy is usually performed. The lesion must be completely removed, and all inflammatory necrotic tissue must be removed during surgery. Immediately after removal of the lesion, nipple reconstruction is performed, and part of the breast gland is displaced for internal reconstruction, so that destruction and reconstruction are completed in a single operation. In this way, the complete excision of the contaminated lesion is ensured, and the breast shape is fully maintained.