Primary Small Cell Carcinoma of the Breast Combined with Invasive Ductal Carcinoma 1

Primary small cell carcinoma of the breast (SmCC) is a rare type of breast cancer and a histological subtype of neuroendocrine breast cancer. There is no standard treatment method, and the prognosis is unknown. It needs to be differentiated from lung metastases. A case of a 52-year-old woman is reported here who was diagnosed with small cell carcinoma combined with invasive ductal carcinoma. Whole-body PET-CT and enhanced MRI of the adrenal glands excluded any other primary disease. The patient received an adjuvant chemotherapy regimen of anthracycline combined with cyclophosphamide, sequential cisplatin, and paclitaxel. The patient was kept under close observation for any changes. This case report reviews the literature on SmCC to better understand its pathology characteristics and therapy. Due to the particularity of the patient's tumour composition, we referred to the treatment plan for small-cell lung cancer and adopted a treatment plan based on cisplatin.