Introduction:
Neuroendocrine tumors (NET) are a highly aggressive heterogeneous group of neoplasms that arise from a combination of neural and hormonal cell types. They most commonly arise from the lungs, small intestine, appendix, and pancreas and less frequently from the thyroid, parathyroid, pituitary and adrenal glands. There are several different classifications based on differentiation of tumor cells in comparison to neighboring non-neoplastic cells, however, in general tumors that are well differentiated are low grade and those with poor differentiation are high grade. Large cell neuroendocrine carcinoma was first proposed by Travis et al. in 1991 and subsequently classified as high grade neuroendocrine carcinoma (HGNEC) by the World Health Organization (WHO) International Histological Classification of Tumours. HGNEC is a rare tumor with unclear clinicopathologic features. Patients typically present with widespread metastatic disease and the prognosis is poor given the high mortality rate. Herein, we describe a rare case of pancreatic HGNEC, large cell type, associated with a Cushing’s syndrome presentation.