Abstract
INTRODUCTION: Primary small cell neuroendocrine carcinoma of the breast (SCNCB) is a very uncommon type of breast cancer. Histology and morphology are virtually indistinguishable from small cell neuroendocrine carcinomas of the lung (SCNCL), mandating a search for a primary site elsewhere in the body. There is no standard approach to treatment as there are only a limited number of cases reported in the literature. This report summarizes a case of primary SCNCB and presents a review of the literature. PRESENTATION OF CASE: A 65-year-old female presented to her gynecologist with a right breast mass. After biopsy, she was diagnosed with a primary SCNCB with regional lymph node involvement. She was treated with chemotherapy and radiation therapy with a good clinical response. DISCUSSION: Due to the rare nature of this tumor, no standard treatment exits. Case reports have described breast conserving therapy combined with neoadjuvant or adjuvant chemotherapy as well as chemoradiation therapy alone for metastatic disease. Both chemotherapy regimens, those used to treat SCNCL and invasive breast cancer, have been described in these reports. CONCLUSION: Primary SCNCB is a very rare type of breast cancer with no standard treatment. Further research is needed to better understand the behavior of this rare tumor in order to develop a standard approach to treatment.