The neural ectodermal origin of the peptide-secreting endocrine glands

Common Origin for All Neuroendocrine Tumors

“…The medullary thyroid carcinoma-pheochromocytoma-neurofibromatosis syndrome is clearly of neural ectodermal origin and is also considered to be a variant of the MEA syndrome Chemodectomas have been found in association with thyroid carcinomas in several patients, and it was postulated that this association is possibly a neural ectodermal dysplasia related to the medullary thyroid carcinoma-pheochromocytoma-neurofibromatosis syndrome ( 1 ) . Medullary thyroid carcinomas have also been associated with functioning parathyroid adenomas (4, 8,13,15,16,17,18,21,24). The association of thyroid and parathyroid adenomas links the two main variants of the MEA syndrome previously mentioned and thus suggests that the entire MEA syndrome may be a dysplasia of neural ectoderm.…”

“…Some of these tumors have also produced insulin, ACTH, and catecholamines (24)(25)(26)(27). They seemed however to be linked by their production of a common hormone, serotonin.…”

“…Other examples would be : Neuroendocrine tumor, bladder, chemodectoma histo!ogic type, secreting catecholamines ( 22,24). Another, neuroendocrine tumors, I thyroid and I1 adrenal medulla, I medullary thyroid carcinoma and I1 pheochromocytoma histologic type, I secreting ACTH ( 3 ) .…”

Calcitonin secretion in congenital nongoitrous cretinism.

“…In mammals, the calcitonin-producing cells (C cells)' of the thyroid gland become incorporated into that organ during embryogenesis after their migration from the neural crest (1). In patients with congenital dysgenesis of the thyroid, the thyroid gland is poorly developed or absent, and thus may not be available as the organ of residence for the C cells.…”

“…However, the thyroid does play an importanit role in the embryogenesis of C cells in mammals. These C cells are derived from neural crest elements present in the fourth pair of pharyngeal pouches (1). During embryogenesis in mammals these neural crest elements migrate to the developing thyroid and become (lisseminated aimong the follicular cells.…”