Primary Small Cell Neuroendocrine Carcinoma of the Breast: A Case Report With Literature Review

Small cell neuroendocrine carcinoma is a high-grade and poorly differentiated tumor typically presenting as primary pulmonary neoplasm. Extrapulmonary small cell carcinoma is rare. Primary small cell neuroendocrine carcinoma of the breast (SCNCB) is extremely rare, with an incidence of less than 0.1% of all breast cancers. Herein, we report imaging features of SCNCB incidentally diagnosed in a 58-year-old woman along with a literature review. The tumor was observed to be a round and circumscribed mass with rim enhancement, heterogeneous intra-tumoral enhancement, and peritumoral edema on MRI. The patient underwent breast-conserving surgery with adjuvant chemotherapy and radiation therapy. No tumor recurrence was observed during the 2-year follow-up visits after surgery.