Yuki Ueda, Hirochika Toyama, Takumi Fukumoto, Yonson Ku
Pancreatic neuroendocrine neoplasms are rare tumors with diverse biological behavior. World Health Organization classifications 2010 of neuroendocrine neoplasms based on Ki67 and Mitotic indexes has been widely accepted as correlating favorably with patient prognosis. WHO classification 2017 has been updated on the basis of recent studies on pathological differentiation of “G3 tumors” in the 2010 classification. Neuroendocrine neoplasms are largely classified into well differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas based on their pathological differentiation. NETs are further classified into NET G1, G2, and G3 based on their Ki67 and Mitotic indexes; NECs are classified as NEC G3. In this review, WHO classification, TNM classification and further prognostic factors are described.
