Although we often don’t think about them, pathologists make up a critical part of the team caring for patients with a neuroendocrine tumor. That is because the appearance of a neuroendocrine tumor under the microscope can provide important information on how the tumor should be treated. The "grade" of the tumor as seen under the microscope is particularly important.
The clinical behavior of neuroendocrine tumors is notoriously difficult to predict. Most are slow growing and some don’t even spread (metastasize). It turns out that subtle changes in how fast the tumor cells are dividing (reproducing) can make a big difference in how the tumors behave. Faster dividing tumors are more likely to spread than are slowly dividing tumors. For this reason, the accurate pathologic examination of neuroendocrine tumors is critical.
For example, in a landmark paper Dr. Trevor Ellison and the team at Johns Hopkins reported on 326 patients who had a neuroendocrine tumor of the pancreas surgically resected (Annals of Surgery 2013, PMID 23673766). They found that tumor grade, how fast the tumor cells are dividing, was the single most important prognostic indicator for these patients.