Laboratory Evaluation of Pheochromocytoma and Paraganglioma

Abstract

BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are potentially lethal yet usually surgically curable causes of endocrine hypertension; therefore, once clinical suspicion is aroused it is imperative that clinicians choose the most appropriate laboratory tests to identify the tumors. CONTENT:Compelling evidence now indicates that initial screening for PPGLs should include measurements of plasma free metanephrines or urine fractionated metanephrines. LC-MS/MS offers numerous advantages over other analytical methods and is the method of choice when measurements include methoxytyramine, the O-methylated metabolite of dopamine. The plasma test offers advantages over the urine test, although it is rarely implemented correctly, rendering the urine test preferable for mainstream use. To ensure optimum diagnostic sensitivity for the plasma test, reference intervals must be established for blood samples collected after 30 min of supine rest and after an overnight fast when measurements include methoxytyramine. Similarly collected blood samples during screening, together with use of age-adjusted reference intervals, further minimize false-positive results. Extents and patterns of increases in plasma normetanephrine, metanephrine, and methoxytyramine can additionally help predict size and adrenal vs extraadrenal locations of tumors, as well as presence of metastases and underlying germline mutations of tumor susceptibility genes.

European Society of Endocrinology Clinical Practice Guideline for long-term follow-up of patients operated on for a phaeochromocytoma or a paraganglioma

“…Phaeochromocytomas and most thoraco-abdomino-pelvic paragangliomas are of sympathetic origin. In most PPGL, chromaffin cells produce one or more catecholamines that are metabolised into MN or 3MT (1,3). Most parasympathetic paragangliomas are found in the head or neck and do not usually produce catecholamines.…”

“…Descriptions of several series have shown that malignant primary tumours are more frequently extraadrenal (paraganglioma rather than phaeochromocytoma) than apparently benign primary tumours (review in (8) and Section 4). High levels of 3MT are found in patients with malignant PPGL (3,10). Primary malignant tumours and malignant recurrences are frequent in SDHB mutation carriers and may also occur in FH and MDH2 mutation carriers (1,4,5,6,7,8,9 …”

Personalized diagnostics of chromaffin tumors (pheochromocytoma, paraganglioma) in oncoendocrinology

“…У пациентов с биохимически "молчащими" опухолями определение уровня хромогранина А как универсального биомаркера нейроэндо-кринных опухолей является важным вспомо-гательным тестом [58].…”

Quando hipertensão arterial persistente no adolescente tem uma origem endócrina rara: relato de dois casos e revisão da literatura

“…Estima-se uma taxa de recorrência de 1/100 casos (sendo mais de 40% destas recorrências correpondentes a casos de malignidade) [7,52]. Sendo assim, recomenda-se em todos os pacientes uma monitorização laboratorial anual (metanefrinas plasmáticas ou urinárias e cromogranina A) e com exames de imagem (ponderar a realização de ressonância magnética tóraco-abdomino-pélvica a cada um ou dois anos) [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

“…Os tumores secretores de catecolaminas têm origem em células cromafins da medula da suprarrenal no caso dos feocromocitomas (estes são tumores total ou parcialmente encapsulados, muito vascularizados, sendo que 85 a 95% são tumores únicos, com diâmetro inferior a 5 cm); e dos gânglios simpáticos extra-adrenais no caso dos paragangliomas (cabeça e pescoço em 70%, região abdomino-pélvica em 20% e torácica em 10%) [7,13,[15][16][17][18]. Até 47% dos feocromocitomas são malignos, e como não há características histológicas, bioquímicas ou de microscopia eletrônica para a malignidade, esta é definida exclusivamente pela presença de metástases (sobretudo nos gânglios linfáticos, fígado, pulmão e osso) [7,15,17,[19][20][21][22].…”