Based on the 2017 World Health Organization (WHO) classification, P-NEN are divided into well-differentiated P-NETs: grade 1 (G1), Ki-67 <3% and/or mitotic rate <2 mitoses/2 mm2; grade 2 (G2), Ki-67: 3–20% and/or mitotic rate 2–20 mitoses/2 mm2; grade 3 (G3), Ki-67 > 20%; and poorly-differentiated pancreatic neuroendocrine carcinoma (P-NEC) including small-cell type (SCNEC) and large-cell type (LCNEC), Ki-67 > 20% and/or mitotic rate >20/2 mm2 (4). Here, MKI67 is linked to large cell neuroendocrine carcinoma.