Pheochromocytoma and paraganglioma
Pheochromocytoma and paraganglioma are catecholamine-secreting tumors of adrenal medullary chromaffin cells and extra-adrenal sympathetic ganglia, causing sustained or paroxysmal hypertension with headache, sweating, and palpitations, diagnosed by plasma free or 24-hour urine fractionated metanephrines before any imaging is obtained. First-line treatment is surgical resection preceded by alpha blockade with phenoxybenzamine (or off-label doxazosin) for 10 to 14 days, with a beta blocker added only after alpha blockade is established.
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What this article covers
- Overview
Pheochromocytomas and paragangliomas are catecholamine-secreting neuroendocrine tumors arising from chromaffin cells: about 90% arise in the adrenal medulla (pheochromocytoma) and the remainder from…
- Epidemiology
Pheochromocytoma is rare, with an incidence of about 2 to 8 cases per million persons per year and a prevalence of about 0.5% among patients with hypertension.
- Risk factors
A germline mutation is the dominant identifiable risk factor, present in at least one third of patients.
- Pathophysiology
Autonomous, poorly regulated secretion of catecholamines (epinephrine, norepinephrine, and sometimes dopamine) from chromaffin tumor cells is the central mechanism, bypassing normal feedback control of sympathoadrenal output.
- Clinical features
The classic triad of headache, diaphoresis, and palpitations (with or without hypertension) occurs in fewer than half of patients, so its absence does not exclude the diagnosis; spells are typically…
- Differential diagnosis
Primary (essential) hypertension: lacks the paroxysmal spells and diaphoresis of catecholamine excess; metanephrine levels are normal rather than markedly elevated.
- Diagnosis
The diagnosis is established biochemically, not by imaging or histology: plasma free metanephrines more than four times the upper limit of normal (in the absence of acute stress or illness), or…
- Management
The first action is preoperative alpha-adrenergic blockade, not immediate surgery, because unopposed catecholamine release during tumor manipulation can precipitate a hypertensive crisis; alpha…
- Complications
Hypertensive crisis can occur spontaneously, with anesthesia induction, during tumor palpation, or if a beta blocker is started before adequate alpha blockade, and can be fatal without prompt phentolamine.
- Prognosis
Most pheochromocytomas and paragangliomas are benign, and surgical resection after adequate blockade is generally curative for localized disease.
- Prevention
There is no primary prevention for sporadic pheochromocytoma, so prevention centers on early detection in patients with a recognized testing indication: adrenergic spells, resistant hypertension on…
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