Primary Neuroendocrine Tumor of the Breast: A Rare Case

Primary neuroendocrine tumors (NETs) predominantly affect postmenopausal women. This case study focused on a 54-year-old woman who presented with a painless right breast lump. While the lump exhibited estrogen and progesterone receptor (PR) positivity, it lacked human epidermal growth factor receptor 2 expression. Further evaluation revealed positivity for the neuroendocrine markers chromogranin A (CGA) and synaptophysin (SYN). It also revealed a 3% positive Ki-67 proliferation index. Treatment for neuroendocrine breast cancer (NEBC) mirrors that of standard invasive breast cancer: breast conservation or mastectomy combined with sentinel lymph node biopsy or axillary dissection. The patient underwent a right mastectomy with sentinel lymph node biopsy, followed by hormonal therapy based on her tumor's immunohistochemical profile. Due to the low incidence and limited research on primary NETs, their exact origin remains shrouded in mystery. Accurate diagnosis, specific treatment options, and long-term prognosis remain significant challenges in managing this rare form of breast cancer.