The tail of neuroendocrine tumors from lung to pancreas: Two rare case reports

INTRODUCTION: Primary pancreatic neuroendocrine tumors are a well-established disease entity, however, neuroendocrine metastases to the pancreas from other sites have been scarcely documented. Specifically, pancreatic metastases from a pulmonary carcinoid tumor have only previously been described in a single case report. PRESENTATION OF CASE: We sought to outline our institutional experience of two patients with pulmonary neuroendocrine tumors that developed metastases to the pancreas, confirmed by gross pathology and immunohistochemistry. In both cases, the pancreatic metastases were surgically resected and their pulmonary origin were discovered post-operatively. DISCUSSION: Our findings should raise awareness to the possibility of metastatic disease when evaluating a pancreatic mass in a patient with a clinical history of pulmonary carcinoid tumor. Expert opinion on immunohistochemically differentiating a primary pancreatic neuroendocrine malignancy from a metastasis should be employed in these cases. CONCLUSION: Establishing this diagnosis pre-operatively could affect the decision to proceed with surgical resection, given the morbidity of pancreatectomy and the unknown long-term clinical outcome of patients with pulmonary carcinoid tumors metastatic to the pancreas.