SYP and neuroendocrine neoplasm: Neuroendocrine neoplasms are a rare and heterogenous group of tumors arising from multiple anatomic sites with characteristic histology and immunohistochemistry.[7] MiNEN express a wide spectrum of biomarkers of neuroendocrine differentiation (Chromogranin A, CD56, and synaptophysin) on the neuroendocrine compartment as well as site specific markers such as CK20 and Caudal Type Homeobox 2 on adenocarcinoma compartment.