The histopathology diagnosis requires both morphological characteristics and the identification of neuroendocrine markers by immunohistochemistry (IHC), specifically using markers such as chromogranin A, synaptophysin, neuron-specific enolase (NSE), CD56 (neural cell adhesion molecule), and Ki-67 for histological grading, and allowing differentiation from neuroendocrine tumors (NETs) (38). Here, ENO2 is linked to neuroendocrine neoplasm.