A case of small cell carcinoma of the breast

Abstract

A 67-year-old woman with a mass in the right breast was admitted to our hospital. The tumor measured 35 mm in diameter in the right breast, and the lymph node measured 30 mm in diameter in the right axilla. The mass was diagnosed as malignant based on core needle biopsy. Immunohistochemistry staining for synaptophysin, chromogranin A, and CD56 was positive, suggesting that the tumor was small cell carcinoma. Positron emission tomography-computed tomography imaging excluded any other primary disease. Thus, the patient was diagnosed as having primary small cell carcinoma of the breast. Modified radical mastectomy with axillary lymph node dissection was performed. The pathological diagnosis of the surgical material confirmed small cell carcinoma. The expression of estrogen, progesterone, and human epidermal growth factor receptors was negative. After surgery, chemotherapy- and radiotherapy-based breast cancer treatment were performed. The patient was relapse free 9 months after surgery.