Rationale: Metaplastic breast cancer (MBC) is a rare tumor of the breast, and skin ulceration of breast tumors is a difficult clinical problem that reduces the patient's quality of life.Patient concerns: There are currently no Standard Treatment Guidelines for MBC at present, and the treatment for the skin ulceration of breast tumors is limited in clinics.Diagnosis: Here, we report the case of a patient with a large MBC and skin ulceration, accompanied by exudation and odor.Intervention: The combined treatment of albumin paclitaxel and carrelizumab (anti-PD-1 immunotherapy) was effective in reducing the tumor, but it increased the severity of the skin ulceration. After taking traditional Chinese medicine, the skin ulceration healed completely. Then the patient underwent a mastectomy and radiotherapy.Outcomes: The patient has a high quality of life and was in good condition after the comprehensive treatment.Lessons: This suggests that traditional Chinese medicine may have a good auxiliary therapeutic effect on the skin ulceration of MBC.