A complete pathological response to preoperative chemotherapy in a male patient with primary neuroendocrine breast cancer: a case report

BACKGROUND: Primary neuroendocrine carcinoma (small-cell carcinoma) of the breast is a rare tumor; most cases are reported in women. Small-cell carcinoma is a type of neuroendocrine tumor characterized by high-grade, poorly differentiated, and aggressive behavior, which are common features regardless of the tumor's location. Here, we present a rare case of primary small-cell carcinoma of the breast in a male patient treated successfully with neoadjuvant chemotherapy followed by surgery. CASE PRESENTATION: A 47-year-old Syrian man presented with a left breast mass. Further histopathological investigation revealed the diagnosis of high-grade small-cell carcinoma of the breast. Computed tomography imaging excluded other potential primary origins. The patient was treated with neoadjuvant chemotherapy (cisplatin and etoposide), followed by a modified radical mastectomy. After 18 months of diagnosis, the patient is under surveillance and doing well. CONCLUSION: This report presents a rare case of male breast cancer with the uncommon histological diagnosis of small-cell carcinoma. It highlights a successful therapeutic approach in the absence of established treatment guidelines.