An update on the diagnosis of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs) arise from neuroendocrine cells found throughout the gastrointestinal tract and islet cells of the pancreas.The incidence and prevalence of GEP-NENs have been increasing each year due to higher awareness,improved diagnostic modalities,and increased incidental detection on cross-sectional imaging and endoscopy for cancer screening and other conditions and symptoms.GEP-NENs are a heterogeneous group of tumors and have a wide range in clinical presentation,histopathologic features,and molecular biology.Clinical presentation most commonly depends on whether the GEP-NEN secretes an active hormone.The World Health Organization recently updated the classification of GEP-NENs to introduce a distinction between high-grade neuroendocrine tumors and neuroendocrine carcinomas,which can be identified using histology and molecular studies and are more aggressive with a worse prognosis compared to high-grade neuroendocrine tumors.As our understanding of the biology of GEP-NENs has grown,new and improved diagnostic modalities can be developed and optimized.Here,we discuss clinical features and updates in diagnosis,including histopathological analysis,biomarkers,molecular techniques,and radiology of GEP-NENs.We review established diagnostic tests and discuss promising novel diagnostic tests that are currently in development or require further investigation and validation prior to broad utilization in patient care.