Small cell carcinoma is the cancer of the lung but, rarely can be seen in the breast. In this paper, the clinical and pathological features and treatment of small cell breast carcinoma diagnosed in a fiftyone year old female patient is outlined with the context of current literature. The patient presented with a lump in her left breast. On physical examination, a hard, semi-mobile mass was palpated. At tru-cut biopsy, the tumoral tissue was composed of atypical epithelial cells, some with fusiform structure and invasive, solid growth pattern in fibrous stroma. Immunohistochemically, the cells were stained diffusely and homogenously with NSE, synaptophysin, TTF-1 and CK7. There was no staining with myoepithelial markers (p63, calponin), GCDFP 15, CK20, and mammoglobulin. Ki67 proliferative index was 90%. Estrogen receptor was negative, progesteron receptor was 30% positive and cerbB2 score was 0. With these findings, the tumor was diagnosed as ”small cell breast carcinoma with neuroendocrine features”. After surgery, cyclophosphamide and adriamycine chemotherapy was given for four cycles. Additional carboplatin and etoposide combination chemotheraphy was given for three cycles. It is known that small cell breast cancers are high grade tumors with increased lymphovascular invasion and mostly negative hormone receptors and therefore they have low survival rates. But with the introduction of agents like platins, etoposide and irinotecan into the systemic treatment of small cell carcinoma of the lung, longer survival periods have been started to be reported.
Keywords: breast carcinoma, small cell carcinoma, neuroendocrine tumor