Introduction:
Invasive carcinoma with neuroendocrine features is a rare entity that accounts for 2-5% of all invasive carcinoma of the breast (1). It has comparable histological features with other neuroendocrine tumors of the gastrointestinal tract, pancreas, and bronchopulmonary system with different percentages of neuroendocrine markers. The diagnosis of the neuroendocrine tumors of the breast is specially done based on immunohistochemistry which is not routinely done for the tumors of the breast, so the exact incidence is still unknown (2). Some literature report that neuroendocrine tumors are seen in up to 30% of invasive carcinoma commonly associated with solid papillary carcinoma, invasive ductal carcinoma, and mucinous carcinoma of the breast (3). A novel hypothesis states that the tumor arises from differentiating neoplastic stem cells into epithelial and endocrine lines as a consequence of the unusual differentiating event during carcinogenesis (4). The neuroendocrine markers like chromogranin A or B and synaptophysins are generally positive for these cancers (5). Here, we present a case of a rare variant of the invasive ductal breast with neuroendocrine differentiation.