Endocrine and neuroendocrine cells form a large and diverse array of cell types. 
They are present in the form of specialized organs, such as the pituitary, 
parathyroid, thyroid, and adrenal gland, or in the form of the diffuse 
neuroendocrine system in the respiratory and digestive tracts. Neuroendocrine 
tumors are a heterogeneous group of neoplasms, yet they present certain unifying 
features. These include frequent hormonal overproduction that leads to specific 
symptoms and a typical immunohistochemical staining profile with chromogranin A 
and synaptophysin reactivity. Over the past decades, many neuroendocrine tumors 
have been described in the context of heritable tumor syndromes, and there exist 
several syndromes that are almost entirely composed of neuroendocrine tumors. 
Tumors occurring as part of these hereditary syndromes are characterized by 
specific genetic abnormalities that have helped our understanding of 
tumorigenesis, and they frequently appear at a young age. It is therefore 
important for the pediatric pathologist to be aware of specific histologic 
characteristics of neuroendocrine tumors in childhood and of their association 
with specific tumor syndromes. This may alert other clinicians to the 
possibility of multiple tumors in the patient or his family members. This review 
focuses on hereditary syndromes with neuroendocrine tumors, including multiple 
endocrine neoplasia types 1 and 2, Von Hippel-Lindau disease, neurofibromatosis 
type 1, Carney complex, pheochromocytoma-paraganglioma syndrome, and familial 
nonmedullary thyroid carcinoma. In addition, several individual neuroendocrine 
tumors are described, such as medullary thyroid carcinoma, 
gastroenteropancreatic tumors, pheochromocytoma, and paraganglioma, emphasizing 
specific histopathologic characteristics.