The appropriate pathological (histopathology and immunohistochemistry) diagnosis of P-NET should include the functional evaluation by specific staining for peptide hormones (insulin, serotonin and other amines depending on the clinical symptoms), Chromogranin A and synaptophysin and the establishment of tumor grade by reporting the ki67 index and the mitotic count per 2 mm2 [9,10,11]. Here, INS is linked to neoplasm.