PanNET Grade 3 vs PanNEC Grade 3
This slide contrasts pancreatic neuroendocrine tumor (PanNET) Grade 3 with pancreatic neuroendocrine carcinoma (PanNEC) Grade 3. The 2010 WHO Classification of Pancreatic Neuroendocrine Neoplasms consisted of neuroendocrine tumor (NET) Grade 1, NET Grade 2, and neuroendocrine carcinoma Grade 3. The 2017 WHO Classification was modified to include NET Grade 1, NET Grade 2, NET Grade 3 and NEC Grade 3. i.e. in the revised grading system, there is a new category of well-differentiated NET (NET Grade 3) that have high mitotic activity and Ki-67 proliferation index and could technically be classified as Grade 3 neuroendocrine carcinomas. However, their molecular pathogenesis and biology is similar to the better-differentiated Grade 1 or 2 NET. They are somewhat more aggressive than Grade 2 PanNET but not as rapidly progressive as PanNEC. Moreover, they don't respond to the chemotherapy regimen used in the treatment of poorly-differentiated grade 3 NEC.