Primary small cell carcinoma of the breast: a case report

Neuroendocrine breast cancer is a rare entity that was defined in 2003 by the World Health Organization as a separate breast cancer subtype. The diagnosis of neuroendocrine breast cancer requires the presence of neuroendocrine features in at least 50% of malignant cells, the exclusion of non-mammary primary tumors, as well as the presence of an in situ component in breast histology. The treatment and prognosis of neuroendocrine breast cancer are still not well established. Small cell carcinoma of the breast is a subtype of neuroendocrine cancer, resembling small cell carcinoma of the lung. It has a very poor prognosis and warrants treatment with platinum-based chemotherapy.

We herein report the case of a 47-year-old white woman with a left breast mass that was found to be an early-stage, high-grade small cell carcinoma of the breast. Positron emission tomography-computed tomography imaging excluded any other primary disease. Our patient underwent a left total mastectomy with sentinel lymph node biopsy and received cisplatin-based adjuvant chemotherapy. Our patient remains free of disease to date.

This case report sheds light on a rarely described disease and provides a comprehensive approach to diagnosis and management. Neuroendocrine carcinoma of the breast is a well-defined histologic subtype of breast cancer. Small cell carcinoma of the breast is a rare subtype of neuroendocrine breast cancer. Due to the rarity of this entity, prognosis has still not been well established, and treatment has not been standardized, cisplatin-based treatment has been used in this case similar to small cell carcinoma of the lung.