Abstract:
Neuroendocrine neoplasms (NENs) are a group of heterogeneous tumors with neuroen-
docrine differentiation that can arise from any organ. They account for 2% of all malignancies
in the United States. A significant proportion of NEN patients experience endocrine imbalances
consequent to increased amine or peptide hormone secretion, impacting their quality of life and
prognosis. Over the last decade, pathologic categorization, diagnostic techniques and therapeutic
choices for NENs—both well-differentiated neuroendocrine tumors (NETs) and poorly differen-
tiated neuroendocrine carcinomas (NECs)—have appreciably evolved. Diagnosis of NEN mostly
follows a suspicion from clinical features or incidental imaging findings. Hormonal or non-hormonal
biomarkers (like serum serotonin, urine 5-HIAA, gastrin and VIP) and histology of a suspected NEN
is, therefore, critical for both confirmation of the diagnosis and classification as an NET or NEC.
Therapy for NENs has progressed recently based on a better molecular understanding, including
the involvement of mTOR, VEGF and peptide receptor radionuclide therapy (PRRT), which add to
the growing evidence supporting the possibility of treatment beyond complete resection. As the
incidence of NENs is on the rise in the United States and several other countries, physicians are more
likely to see these cases, and their better understanding may support earlier diagnosis and tailoring
treatment to the patient. We have compiled clinically significant evidence for NENs, including rele-
vant changes to clinical practice that have greatly updated our diagnostic and therapeutic approach
for NEN patients.