In 2010, the World Health Organization released a new classification system for endocrine pancreatic tumors. The new categories replaced those in the old classification.
To test the safety and accuracy of the new classification in stratifying patients, we retrospectively evaluated 64 consecutive patients, surgically R0 resected for pancreatic endocrine tumors.
In our experience, only 19/31 (61.3%) patients classified as having well-differentiated tumors were included in the new neuroendocrine tumor G1 category while the remaining 12 (38.7%) shifted into the G2 category. Moreover, 10/33 (30.3%) patients classified as affected by a malignant endocrine neoplasm in the old system were considered as G1 tumors in the new one. These differences were statistically significant (P