University of Florence, Dept. Clinical Pathophysiology, Viale Pieraccini 6, 50139 Florence, Italy.
Best Pract Res Clin Endocrinol Metab. 2012 Aug;26(4):507-15. doi: 10.1016/j.beem.2011.10.008. Epub 2012 May 22.
Phaeochromocytomas and paragangliomas are neural crest-derived tumours. Autopsy studies indicate that relatively large numbers of these tumours remain undiagnosed during life. This may reflect non-specific signs and symptoms and low medical alertness in evaluating the clinical picture or it may reflect a silent clinical presentation - the subclinical phaeochromocytoma. The associated clinical picture depends on the capacity of the tumours to release catecholamines and sometimes biologically active peptides. Hypertension is the hallmark of catecholamine release, but the amount, type and pattern of catecholamine secretion is extremely variable. Some tumours have low or intermittent secretory activity, some produce mainly or solely dopamine, while others very rarely do not synthesize or release any catecholamines (non-secretory or non-functional tumours). Such tumours may present with mild or even absent signs and symptoms of catecholamine excess. Low secretory activity may reflect small tumour size or differences in secretory phenotypes associated with the biochemical and genetic background of the tumours. Tumours due to succinate dehydrogenase subunit B mutations are often subclinical, poorly differentiated, contain low amounts of catecholamines, and are usually malignant at diagnosis. Adrenoceptor desensitization can result in a subclinical presentation, even when catecholamine levels are high. Subclinical phaeochromocytomas are often discovered as incidentalomas during radiological procedures or during routine screening for phaeochromocytoma in carriers of mutations in one of the ten currently identified tumour susceptibility genes. Undiagnosed phaeochromocytomas, whether or not subclinical and even if biologically benign, may cause extremely deleterious consequences or even death, following abrupt release of catecholamines.
嗜铬细胞瘤和副神经节瘤是由神经嵴衍生而来的肿瘤。尸检研究表明，这些肿瘤在生前有相当数量未被诊断出来。这可能反映了非特异性的症状和体征，以及在评估临床表现时医疗警觉性较低，或者可能反映了隐匿性的临床表现——亚临床嗜铬细胞瘤。相关的临床表现取决于肿瘤释放儿茶酚胺的能力，有时还取决于生物活性肽。高血压是儿茶酚胺释放的标志，但儿茶酚胺的分泌量、类型和模式是极其多变的。有些肿瘤的分泌活性低或间歇性，有些主要或仅产生多巴胺，而有些则非常罕见地不合成或释放任何儿茶酚胺（无分泌或无功能的肿瘤）。这些肿瘤可能表现出轻度甚至没有儿茶酚胺过多的症状和体征。低分泌活性可能反映肿瘤体积小，或与肿瘤生化和遗传背景相关的分泌表型差异。琥珀酸脱氢酶亚基 B 突变引起的肿瘤通常是亚临床的、低分化的，含有低水平的儿茶酚胺，并且在诊断时通常是恶性的。肾上腺素能受体脱敏可导致亚临床表现，即使儿茶酚胺水平较高也是如此。亚临床嗜铬细胞瘤通常在影像学检查过程中或在携带目前已鉴定的 10 个肿瘤易感性基因之一的突变的情况下进行嗜铬细胞瘤常规筛查时被偶然发现为偶发瘤。未被诊断的嗜铬细胞瘤，无论是否为亚临床，即使生物学上良性，在儿茶酚胺突然释放后，也可能导致极其有害的后果，甚至死亡。
