Adrenal medulla tumors

Phentolamine, another alpha blocker is exclusively used for the diagnosis of pheochromocytoma and for the prevention of abrupt rise in blood pressure during surgical removal of adrenal medulla tumors. 

At 2 years, adrenal medulla tumors occurred with positive trends in male rats, and the incidences in the 550 and 1100mgm groups were significantly increased. Also, a slightly increased incidence of renal adenomas occurred in the 1100mgm group. Non-neoplastic lesions related to Stoddard Solvent exposure occurred in the kidney of male rats. 

Pheochromocytoma A tumor arising from chromaffin cells, most commonly found in the adrenal medulla. The tumor causes the adrenal medulla to hypersecrete epinephrine and norepinephrine, resulting in hypertension and other signs and symptoms of excessive sympathetic nervous system activity. The tumor is usually benign but may occasionally be cancerous. 

Phaeochromocytoma (a tumor in the adrenal medulla) is not uncommon in rats, but rare in humans. Pheochromocytomas are induced in rats by a variety of non-genotoxic substances that may act indirectly by stimulating chromaffin cell proliferation. They are not known to be similarly inducible in other species. In the rat, a mechanism for the development may be hypercalcaemia (Tischler et al. 1999 Capen et ah, in Haschek et al. 2001). 

Two-year animal inhalation studies have shown nickel oxide and nickel subsulfide to be carcinogenic in rats, resulting in alveolar/bron-chiolar adenomas and tumors of the adrenal medulla nickel subsulfide was not carcinogenic to mice, whereas nickel oxide caused equivocal evidence of carcinogenicity in mice based on alveolar/bronchiolar adenomas and carcinomas.Nickel sulfate was not carcinogenic in rodent assays but did cause an inflammatory response in the lungs of animals. 

Pheochromocytoma is a tumor of the adrenal medulla or sympathetic ganglion cells. The tumor secretes catecholamines, especially norepinephrine and epinephrine. The patient in the case study at the beginning of the chapter had a left adrenal pheochromocytoma that was identified by imaging. In addition, she had elevated plasma and urinary norepinephrine, epinephrine, and their metabolites, normetanephrine and metanephrine. 

The major clinical use of both phenoxybenzamine and phentolamine is in the management of pheochromocytoma. Pheochromocytoma is a tumor usually found in the adrenal medulla that releases a mixture of epinephrine and norepinephrine. Patients have many symptoms and signs of catecholamine excess, including intermittent or sustained hypertension, headaches, palpitations, and increased sweating. 

Pheochromocytomas are catecholamine-producing tumors that arise from chromaffin cells of the adrenal medulla. Excluding neuroblastomas, about 10% of catecholamine-producing tumors arise from extraadrenal sympathochro-maffin tissue, usually in the abdomen, and are known as... 

NE secretory protein-55 (NESP-55) is a 241 amino acid polypeptide that is a member of the chromogranin family. It is expressed exclusively in endocrine and neuronal tissue but has a less wide distribution than chromogranin A in human tissues. The reactivity of NESP-55 appears to be restricted to endocrine tumors of the pancreas and adrenal medulla, and several studies have indicated that it may be useful in the identihcation of sites of origin of metastatic endocrine tumors. 

Synaptophysin, also called protein p38, is a glycoprotein initially found in small vesicle membranes of neurons and of chromaffin cells in the adrenal medulla. It has been routinely used as a broad-spectrum marker in normal and neoplastic neuroendocrine cells including those of the pancreas however, strong synaptophysin immunoreactivity has been well-documented in tumors without any endocrine differentiation including solid-pseudopapillary neoplasm (SPN) of the pancreas, which is one of the most important differential diagnoses of endocrine neoplasia in this organ. 

Use of tricyclics in the presence of catecholamine-secreting tumors of the adrenal medulla (e.g., pheochromocytoma, neuroblastoma), may precipitate a hypertensive crisis, due to the increase in catecholamine production in the face of decreased adrenergic reuptake. 

A patient with a tumor of the adrenal medulla experienced palpitations, excessive sweating, and hypertensive headaches. His urine contained increased amounts of vanillylmandelic acid. His symptoms are probably caused by an overproduction of which of the following ... 

Pheochromocytoma A tumor that resembles the adrenal medulla consisting of cells that release varying amounts of norepinephrine, epinephrine, or both into the circulation... 

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