Canadian Medical Guide > Diseases > Neoplasms > Neoplasms by Histologic Type > Neoplasms, Germ Cell and Embryonal > Neuroectodermal Tumors > Neuroendocrine Tumors Terms and Definitions

Neuroendocrine Tumors

Medical Definition:	Tumors whose cells possess secretory granules and originate from the neuroectoderm, i.e., the cells of the ectoblast or epiblast that program the neuroendocrine system. Common properties across most neuroendocrine tumors include ectopic hormone production (often via apud cells), the presence of tumor-associated antigens, and isozyme composition.
Guide Notes:	/blood supply /chem /second /secret /ultrastruct permitted; coord IM with precoord organ/neopl term (IM)

Neuroendocrine Tumors Categories.

	Adenoma, Acidophil - A benign tumor, usually found in the anterior lobe of the pituitary gland, whose cells stain with acid dyes. Such pituitary tumors may give rise to excessive secretion of growth hormone, resulting in gigantism or acromegaly. A specific type of acidophil adenoma may give rise to nonpuerperal galactorrhea. (Dorland, 27th ed)
	Adenoma, Basophil - A small tumor of the anterior lobe of the pituitary gland whose cells stain with basic dyes. It may give rise to excessive secretion of ACTH, resulting in CUSHING SYNDROME. (Dorland, 27th ed)
	Adenoma, Chromophobe - A benign tumor of the anterior pituitary in which the cells do not stain with acidic or basic dyes.
	Apudoma - A general term collectively applied to tumors associated with the APUD cell series irrespective of their specific identification.
	Carcinoid Tumor - A usually small, slow-growing neoplasm composed of islands of rounded, oxyphilic, or spindle-shaped cells of medium size, with moderately small vesicular nuclei, and covered by intact mucosa with a yellow cut surface. The tumor can occur anywhere in the gastrointestinal tract (and in the lungs and other sites); approximately 90% arise in the appendix. It is now established that these tumors are of neuroendocrine origin and derive from a primitive stem cell. (From Stedman, 25th ed & Holland et al., Cancer Medicine, 3d ed, p1182)
	Carcinoma, Neuroendocrine - A group of carcinomas which share a characteristic morphology, often being composed of clusters and trabecular sheets of round "blue cells", granular chromatin, and an attenuated rim of poorly demarcated cytoplasm. Neuroendocrine tumors include carcinoids, small ("oat") cell carcinomas, medullary carcinoma of the thyroid, Merkel cell tumor, cutaneous neuroendocrine carcinoma, pancreatic islet cell tumors, and pheochromocytoma. Neurosecretory granules are found within the tumor cells. (Segen, Dictionary of Modern Medicine, 1992)
	Melanoma - A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)
	Neurilemmoma - A neoplasm that arises from SCHWANN CELLS of the cranial, peripheral, and autonomic nerves. Clinically, these tumors may present as a cranial neuropathy, abdominal or soft tissue mass, intracranial lesion, or with spinal cord compression. Histologically, these tumors are encapsulated, highly vascular, and composed of a homogenous pattern of biphasic fusiform-shaped cells that may have a palisaded appearance. (From DeVita Jr et al., Cancer: Principles and Practice of Oncology, 5th ed, pp964-5)
	Paraganglioma - A neural crest tumor usually derived from the chromoreceptor tissue of a paraganglion, such as the carotid body, or medulla of the adrenal gland (usually called a chromaffinoma or pheochromocytoma). It is more common in women than in men. (Stedman, 25th ed; from Segen, Dictionary of Modern Medicine, 1992)
	Prolactinoma - A pituitary adenoma which secretes PROLACTIN, leading to HYPERPROLACTINEMIA. Clinical manifestations include AMENORRHEA; GALACTORRHEA; IMPOTENCE; HEADACHE; visual disturbances; and CEREBROSPINAL FLUID RHINORRHEA.

Neuroendocrine Tumors Medical Definitions and Terms

CANADIAN MEDICAL GUIDE

Thank you for visiting Canadian Medical Guide .com

Wildlife On Video »

Canada's Great Outdoors
Tour Canadian Rockies »
Book Banff »
Book Jasper »
Maligne Lake Boat Cruise »
Gondola Banff »
Hike Jasper »
Jasper Columbia Icefield »