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Pheochromocytomas and paragangliomas are chromaffin cell tumors that produce, store (e.g. in vesicles), metabolize (e.g. to yield metabolites such as normetanephrine or metanephrine), and secrete (release) catecholamines (e.g. norepinephrine and epinephrine, or dopamine). The metabolism of catecholamines is a more consistent process than that of catecholamine secretion. Pheochromocytomas are found in the adrenal gland; closely related tumors of extra-adrenal location are classified as paragangliomas. Most pheochromocytoma and paraganglioma tumors (PTTs) represent sporadic tumors but about 20-30% of these tumors are familial. Mutations in six genes to date have been identified to be responsible for familial PTTs: 1. the von Hippel-Lindau (VHL) gene leading to VHL syndrome; 2. the RET gene leading to multiple endocrine neoplasia type 2; 3. the neurofibromatosis type 1 (NF-1) gene associated with von Recklinghausens disease; and 4 and 5. mutations of genes encoding the B, C, and D subunits of mitochondrial succinate-dehydrogenase (SDHB, SDHC, and SDHD) associated with familial PTTs. The presence of catecholamine excess reflects various clinical signs and symptoms associated with PTTs. Hypertension is the most common sign and may be sustained or paroxysmal. Numerous independent studies have now confirmed that measurements of fractionated metanephrines (i.e. normetanephrine and metanephrine measured separately) in urine or plasma provide superior diagnostic sensitivity over measurement of the parent catecholamines. Current localization of PTTs should be based on the use of anatomical as well as specific functional imaging studies to proof that a tumor is indeed pheochromocytoma or paraganglioma. Laparoscopic surgery is now the technique of first choice for resection adrenal and extra-adrenal PTTs. All patients with PTTs should receive appropriate preoperative medical management to block the effects of released catecholamines (blocking the synthesis and the action of catecholamines). Currently, there is no curative treatment for malignant PTTs.

MeSH
alfa blokátory terapeutické užití MeSH
alfa-methyltyrosin terapeutické užití MeSH
diferenciální diagnóza MeSH
fenoxybenzamin terapeutické užití MeSH
feochromocytom diagnóza genetika chirurgie MeSH
lidé MeSH
magnetická rezonanční tomografie metody MeSH
metastázy nádorů terapie MeSH
paragangliom diagnóza genetika chirurgie MeSH
Check Tag
lidé MeSH
Publikační typ
přehledy MeSH

Kniha

Feochromocytom

Pacák, Karel, 1958-
Autor Autorita ORCID

Praha : Galén, c2008

1. vyd. 177 s. : il., tab. ; 23 cm

MeSH
adrenergní receptory fyziologie MeSH
biologické markery moč MeSH
chromafinní systém MeSH
feochromocytom diagnóza genetika terapie MeSH
hypertenze MeSH
katecholaminy biosyntéza farmakologie metabolismus MeSH
Publikační typ
monografie MeSH

Článek

Current approaches and new advances in pheochromocytoma

Pacak, Karel
Autor Pacak, Karel

Diabetologie, metabolismus, endokrinologie, výživa. 2008 ; 11 (2) : 86-93.

ISSN 1211-9326
Medvik
Zdroj

Pheochromocytomas are chromaffin cell tumors that produce, store, metabolize, and secrete catecholamines. The metabolism of catecholamines is a more consistent process than that of catecholamine secretion. Pheochromocytomas typically occur in about 80 % of cases from adrenal medullary chromaffin tissue and in about 20 % of cases from extra-adrenal chromaffin tissues. Most pheochromocytomas represent sporadic tumors and about 20–30 % of pheochromocytomas are familial. Mutations of genes encoding SDHB, SDHD, and rarely SDHC are the most recently identified genetic causes of paraganglioma (extra-adrenal pheochromocytoma). Despite this low incidence, pheochromocytoma must always be considered since if it is identified the condition can be cured in most cases, whereas if left untreated the tumor is likely to be fatal due to catecholamine-induced malignant hypertension, heart failure, myocardial infarction, stroke, ventricular arrhythmias, or metastatic disease. Laparoscopic surgery is now the technique of first choice for resection of adrenal and extra-adrenal pheochromocytomas. Although several therapeutic options exist for patients with metastatic pheochromocytoma, all are limited and there is no cure.