Pancreatic neuroendocrine tumors(PNETs) are an uncommon malignancy,accounting for a small percentage of all pancreatic malignancies.Due to their insidious course,most PNETs present with metastatic disease.Although reports in the literature describe PNET metastasis to the liver,lung and brain,to date there are no reports of stage Ⅳ disease involving the breast.Moreover,the lack of consensus regarding classification and treatment of this entity leaves practitioners without standards of practice or a firm base from which to formulate prognosis.In this report,the case of a previously healthy 51-year-old woman with stage Ⅳ PNET is examined.After combined neoadjuvant therapy with 5-fluorouracil,carboplatin,etoposide and radiation,surgical resection revealed metastatic PNET to the breast and lung,with no microscopic evidence of residual disease within the pancreas.An extensive analysis of the presentation,diagnosis,imaging modalities,treatment options,and prognosis is included in the discussion.As demonstrated by our review,there is a need for further studies to delineate inconclusive evidence with respect to subtype classification,treatment and prognosis of PNETs. Pancreatic neuroendocrine tumors (PNETs) are an uncommon malignancy, accounting for a small percentage of all pancreatic malignancies. Due to their insidious course, most PNETs present with metastatic disease. Although reports in the literature describe PNET metastasis to the liver, lung and brain, to date there are no reports of stage IV disease involving the breast. Moreover, the lack of consensus regarding classification and treatment of this entity leaves practitioners without standards of practice or a firm base from which to formulate prognosis. In this report, the case of a previously healthy 51-year-old woman with stage IV PNET is examined. After combined neoadjuvant therapy with 5-fluorouracil, carboplatin, etoposide and radiation, surgical resected revealed metastatic PNET to the breast and lung, with no microscopic evidence of residual disease within an extensive analysis of the presentation, diagnosis, imaging modalities, treatment options, and prognosis is included in the disc ussion.As demonstrated by our review, there is a need for further studies to delineate inconclusive evidence with respect to subtype classification, treatment and prognosis of PNETs.