adenoma

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Related to Adrenal adenoma: pheochromocytoma

neoplasm

neoplasm or tumor, tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death. Feedback controls limit cell division after a certain number of cells have developed, allowing for tissue repair but not expansion. Tumor cells are less responsive to these restraints and can proliferate to the point where they disrupt tissue architecture, distort the flow of nutrients, and otherwise do damage.

Tumors may be benign or malignant. Benign tumors remain localized as a discrete mass. They may differ appreciably from normal tissue in structure and excessive growth of cells, but are rarely fatal. However, even benign tumors may grow large enough to interfere with normal function. Some benign uterine tumors, which can weigh as much as 50 lb (22.7 kg), displace adjacent organs, causing digestive and reproductive disorders. Benign tumors are usually treated by complete surgical removal. Cells of malignant tumors, i.e., cancers, have characteristics that differ from normal cells in other ways beside cell proliferation. For example, they may be deficient in some specialized functions of the tissues where they originate. Malignant cells are invasive, i.e., they infiltrate surrounding normal tissue; later, malignant cells metastasize, i.e., spread via blood and the lymph system to other sites.

Both benign and malignant tumors are classified according to the type of tissue in which they are found. For example, fibromas are neoplasms of fibrous connective tissue, and melanomas are abnormal growths of pigment (melanin) cells. Malignant tumors originating from epithelial tissue, e.g., in skin, bronchi, and stomach, are termed carcinomas. Malignancies of epithelial glandular tissue such as are found in the breast, prostate, and colon, are known as adenocarcinomas. Malignant growths of connective tissue, e.g., muscle, cartilage, lymph tissue, and bone, are called sarcomas. Lymphomas and leukemias are malignancies arising among the white blood cells. A system has been devised to classify malignant tissue according to the degree of malignancy, from grade 1, barely malignant, to grade 4, highly malignant. In practice it is not always possible to determine the degree of malignancy, and it may be difficult even to determine whether particular tumor tissue is benign or malignant.

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adenoma

[‚ad·ən′ō·mə]
(medicine)
A benign tumor of glandular origin and structure.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
In April 2013, she underwent right adrenalectomy and histological evaluation confirmed an adrenal adenoma. Four months later, she began to suffer from fatigue, mild headaches, bilateral aching, and stiffness of neck and shoulders.
92% of the patients with hyperaldosteronism secondary to primary adrenal adenoma had autoantibodies against AT1R in one study [19], whereas Li et al.
Other causes are cortisol-producing adrenal adenomas and ectopic ACTH producing tumors.
[5,10] recognised that a decrease in attenuation of an adrenal mass between 140 kV and 80 kV is highly specific for an adrenal adenoma. In comparison, adrenal metastases demonstrated an increase in attenuation on DECT.
We present a woman who had Cushing's syndrome of pregnancy that resulted from an adrenal adenoma.
Eight patients had adrenal adenoma, one adrenal micronodule, one focal nodular hyperplasia, and one bilateral adrenal hyperplasia without surgery.
The definitive diagnosis was Cushing Disease in 10 subjects and ACTH-independent Cushing's syndrome due to an adrenal adenoma in 10 subjects.
Medical herbalist Hilary Self, the director of Hilton Herbs, created the formula nine years ago for dogs with Cushing's caused by adrenal adenoma. "However," she says, "a virtually identical product formulated for equine Cushing's disease, which is caused by pituitary adenoma, has proved to be equally successful.
Cortisol-producing adrenal adenoma is indicated by elevation in baseline urine free cortisol (UFC) and a corresponding reduction in plasma androgen secretion in the cortisol-induced suppression of adrenocorticotropin hormone (ACTH) and subsequent androgen producing zona reticularis of the adrenal gland.
(1,10,13) This form of "autoparathyroidectomy" or "parathyroid apoplexy" results in hemorrhagic necrosis of the gland that is similar to processes seen in other endocrine gland neoplasms, namely pituitary apoplexy and adrenal adenoma. Patients may be hypercalcemic as a result of the hyperfunctioning of the preexisting adenoma.
His study involved a series of 210 patients (135 women and 75 men aged 19-81 years) with clinically inapparent adrenal adenoma seen at four Italian referral centers between 1996 and 2000.