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.