Large lumps of non-lactating mastitis take about six months to stabilize and very rarely heal within three months. Non-lactating mastitis often occurs in women around 30 years of age with a history of childbirth and is different from acute suppurative mastitis during lactation. The cause is unclear, no bacteria are cultured in the lesion, and it may be related to traumatic triggers. It often presents with sudden onset of redness, swelling, heat, and pain in the breast that is more pronounced, but the rise in body temperature is not obvious, and can sometimes be accompanied by nodular erythema in both lower extremities. In terms of diagnosis, in addition to clinical manifestations, bacterial cultures are often negative, so antimicrobial treatment is not effective. Treatment with corticosteroids is effective in the early stage, so the disease often appears to be prolonged, recurrent, and sometimes full of holes.