Catecholamine-secreting tumor of adrenal medullary chromaffin cells; classic triad of paroxysmal headache, palpitations, and diaphoresis.
Also known as: pheochromocytoma, paraganglioma, PPGL, chromaffin cell tumor, 10% tumor
Overview
Catecholamine-secreting tumor arising from chromaffin cells. Adrenal medullary tumors are pheochromocytomas; extra-adrenal sympathetic ganglia tumors are paragangliomas (PGL); collectively PPGLs. Up to 40% are now recognized as hereditary.
Epidemiology
Annual incidence ~0.8 per 100,000. Account for ~0.1-0.5% of hypertension cases. Peak age 30-50 (younger if hereditary). The 'rule of 10s' (10% bilateral, 10% extra-adrenal, 10% malignant, 10% familial) has been revised — up to 40% are hereditary with modern testing.
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Chromaffin cells synthesize and store catecholamines (epinephrine, norepinephrine, dopamine). Tumors release catecholamines episodically or continuously, producing the clinical syndrome. Extra-adrenal paragangliomas usually secrete norepinephrine (lack PNMT for epi synthesis). SDHB-mutant tumors are more often metastatic.
Elevated plasma free metanephrines or 24-h urinary metanephrines >2× upper limit + tumor on cross-sectional imaging.
Labs
Plasma free metanephrines (preferred for high pretest probability) OR 24-hour urinary metanephrines and catecholamines (preferred for low pretest probability)
Plasma metanephrines: high sensitivity (>95%) but lower specificity; many false positives from stress, TCAs, levodopa, MAOIs
Sampling conditions: supine for 30 min, fasting, avoid acetaminophen and labetalol (assay interference)
Chromogranin A — adjunct (elevated in many neuroendocrine tumors)
Genetic testing recommended for ALL pheochromocytomas (high hereditary yield)
Imaging
Adrenal CT or MRI after biochemical confirmation
MIBG (iobenguane I-123) or Ga-68 DOTATATE PET/CT if metastatic disease or paraganglioma suspected
Whole-body imaging for SDHB-mutant tumors (high metastatic risk)
Diagnostic algorithm
flowchart TD
A[Paroxysmal HTN, headache,<br/>palpitations, diaphoresis] --> B[Plasma free metanephrines<br/>OR 24-h urine metanephrines]
B --> C{Elevated >2× ULN?}
C -->|No| D[Pheo unlikely]
C -->|Yes| E[Adrenal CT or MRI]
E --> F{Tumor identified?}
F -->|No| G[MIBG or DOTATATE PET<br/>(extra-adrenal paraganglioma)]
F -->|Yes| H[Genetic testing<br/>(MEN2, VHL, NF1, SDH)]
H --> I[Pre-op alpha-blockade<br/>phenoxybenzamine 10-14 days<br/>+ salt and water loading]
I --> J[Add beta-blocker AFTER alpha<br/>(days 3-5; never first)]
J --> K[Laparoscopic adrenalectomy]
K --> L[Post-op surveillance:<br/>annual metanephrines]
Pheochromocytoma — diagnostic workup and preoperative preparation (alpha before beta).
Multi-organ failure during induction of anesthesia or beta-blockade alone
Hyperglycemia, hypocalcemia (rare)
Recurrence or metachronous tumors (especially hereditary)
Metastatic disease (SDHB-mutant most concerning)
Postoperative hypotension and hypoglycemia
PANCE pearls
ALPHA BEFORE BETA — beta-blockade alone can cause unopposed alpha vasoconstriction and lethal hypertensive crisis.
Plasma free metanephrines (or 24-h urinary metanephrines) is the screening test of choice. Single best test.
Acetaminophen, labetalol, TCAs, MAOIs, levodopa, and caffeine cause false-positive metanephrine results.
Screen ALL patients with pheochromocytoma for hereditary syndromes (MEN2, VHL, NF1, SDH mutations).
Always screen for and treat pheochromocytoma BEFORE thyroidectomy in MEN2 (medullary thyroid cancer).
Liberal salt and water during alpha-blockade reverses volume contraction and prevents post-op hypotension.
References
Endocrine Society 2014 — Pheochromocytoma and Paraganglioma: An Endocrine Society Clinical Practice Guideline (Lenders et al., J Clin Endocrinol Metab 2014)
NANETS 2021 — North American Neuroendocrine Tumor Society Consensus Guidelines for Pheochromocytoma and Paraganglioma (Fishbein et al., Pancreas 2021)
ENS@T 2020 — European Network for the Study of Adrenal Tumors guidance on PPGL management
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