Pheochromocytoma Diagnosis and Management

Pathophysiology and Epidemiology

Pheochromocytomas develop from neuroendocrine cells derived from pluripotent neural crest stem cells associated with the autonomic nervous system 1
These rare tumors have an annual incidence of 0.1 to 0.6 per 100,000 population and account for approximately 4% of adrenal incidentalomas 2
Approximately 35% of pheochromocytomas are hereditary, showing autosomal dominant inheritance patterns, often with reduced penetrance 3

Symptoms typically result from catecholamine excess, including sustained or paroxysmal elevations in blood pressure 4
Apprehension or anxiety is also a common symptom 2, 4

Hereditary pheochromocytomas are associated with multiple genetic syndromes, including SDHx genes, VHL, RET, NF1, TMEM127, and MAX 5
SDHB mutations are particularly concerning as they are associated with a higher risk of aggressive behavior, development of metastatic disease, and ultimately death 4, 6

Plasma free metanephrines is the most sensitive and specific single test for biochemical diagnosis 4
Imaging studies, such as CT or MRI of the abdomen, are used for localization after positive biochemical testing 4
Genetic testing should be considered, particularly in patients with a family history of pheochromocytoma/paraganglioma, young age at diagnosis, bilateral or multifocal disease, or extra-adrenal location 3, 4

Complete surgical excision (R0 resection) is the mainstay of potentially curative treatment 4
Cytoreductive surgery might be considered for malignant pheochromocytoma, and radiopharmaceuticals (131I-MIBG) can be used for patients with sufficient MIBG uptake 4

Malignancy is defined only by the presence of metastatic lesions at sites where chromaffin cells are normally absent 4
Risk factors for malignancy include SDHB germline mutation 5 and elevated plasma methoxytyramine (>3x upper limit) 4

Biochemical testing approximately 14 days following surgery to check for remaining disease 4
Long-term follow-up includes clinical evaluation, biochemical testing, and imaging with CT of thorax and abdomen as clinically indicated 4

Maternal imprinting with silencing of the maternal allele occurs for SDHD and SDHAF2, meaning only mutations inherited from the father will cause disease 3

The European Heart Journal reports that beta-blockers given without prior alpha-blockade can cause unopposed alpha-adrenergic stimulation and severe hypertension in patients with pheochromocytoma 7
The American Heart Association, as reported in Hypertension, notes that sustained hypertension occurs in 50% of patients and is related to norepinephrine secretion levels, and increased blood pressure variability is characteristic and represents an independent cardiovascular risk factor 8
The American College of Cardiology, as reported in Hypertension, recommends considering pheochromocytoma in patients with resistant hypertension despite maximal medical therapy, with a diagnostic specificity of 90% when the classic triad of headache, palpitations, and sweating occurs together in a hypertensive patient 8
The European Society of Cardiology, as reported in the European Heart Journal, suggests that medications that affect catecholamine metabolism, including certain antidepressants, sympathomimetics, and contrast agents, can precipitate dangerous catecholamine surges in patients with pheochromocytoma 7

The American College of Medical Genetics recommends genetic testing consideration for any individual with a personal history of or first-degree relative with paraganglioma or pheochromocytoma, as approximately 30-40% of pheochromocytomas are hereditary 9
The American Heart Association, as reported in Hypertension, notes that high-risk scenarios requiring screening include hypertensive patients with neurofibromatosis type 1 over age 30, resistant hypertension, hypertension with adrenal incidentaloma, young-onset severe hypertension, hypertensive crisis during anesthesia, and family history of pheochromocytoma or associated genetic syndromes 8
The European Society of Human Genetics, as reported in Genetics in Medicine, reports that key genetic syndromes include SDHB mutations, MEN2 (RET mutations), Von Hippel-Lindau syndrome, and Neurofibromatosis type 1, with varying degrees of penetrance 10
The American College of Medical Genetics, as reported in Genetics in Medicine, notes that SDHD and SDHAF2 mutations show maternal imprinting, meaning disease only manifests when inherited from the father, which can result in falsely negative family histories when the mutation is maternally inherited 11