The efficacy of gemcitabine combined with immunotherapy in a patient with metastatic metaplastic squamous cell carcinoma of the breast

Objectives: Metaplastic squamous cell carcinoma of the breast is a rare form of breast carcinoma for which there is currently no standard treatment.Case presentation: We report the case of a 33-year-old woman with enlargement in her left breast who was diagnosed with metaplastic squamous cell carcinoma by core needle biopsy. The patient underwent a modified radical mastectomy. The immunohistochemistry showed it was a triple-negative breast cancer: progesterone receptor-negative (PR-), estrogen receptor-negative (ER-), and human epidermal growth factor receptor 2 -negative (HER2-). The patient received 6 cycles of adjuvant chemotherapy with nab-paclitaxel and carboplatin. One year later, she developed lung metastases from squamous cell carcinoma. Immunohistochemical results remained triple-negative (ER-, PR- and HER2-). The patient then received gemcitabine combined with immunotherapy. The patient has been assessed as stable disease so far.Conclusions: Immunotherapy combined with gemcitabine showed good efficacy in the treatment of metastatic metaplastic squamous cell carcinoma of the breast after nab-paclitaxel combined with platinum-based therapy.