Adrenal Surgery Basics
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Direct answer
Adrenal surgery stands on two questions applied to every adrenal mass: is it functional, and is it malignant? An incidentaloma requires biochemical testing for cortisol excess (1 mg overnight dexamethasone suppression test unless overt Cushing's is present), catecholamine excess (plasma or 24-hour urinary fractionated metanephrines) and aldosterone excess in hypertensive or hypokalaemic patients, plus unenhanced CT attenuation to identify lipid-rich adenomas and myelolipomas. Phaeochromocytoma, the tumour not to miss, presents with the classic triad of episodic headache, sweating and palpitations with labile hypertension, follows the 'rule of 10s' (roughly 10 per cent bilateral, familial or malignant, though modern series quote higher), and demands preoperative alpha-blockade with phenoxybenzamine before beta-blockade — never beta-blockade first, which precipitates hypertensive crisis. Laparoscopic adrenalectomy is standard for benign lesions, with open resection for large or suspected carcinomas.
What you must remember
- Surgical anatomy: the short right adrenal vein drains directly into the inferior vena cava (the dangerous step), the left into the left renal vein; arterial supply from inferior phrenic, aorta and renal artery.
- Functional workup of any adrenal mass: 1 mg overnight dexamethasone suppression test for subclinical Cushing's, plasma or urinary metanephrines for phaeochromocytoma, and aldosterone-to-renin ratio for primary aldosteronism.
- Imaging character: unenhanced CT attenuation below about 10 Hounsfield units indicates lipid-rich adenoma; homogeneous washout kinetics support adenoma; macroscopic fat means myelolipoma; irregularity, heterogeneity and size above 4 cm (especially above 6 cm) raise carcinoma concern.
- Phaeochromocytoma: paroxysmal headache, palpitations and sweating; diagnosis by plasma or urinary fractionated metanephrines; rule of 10s for bilateral, familial (RET, VHL, SDH, MEN2) and malignant disease.
- Preoperative preparation: alpha-blockade first (phenoxybenzamine, with liberal salt and fluid loading), adding beta-blocker only after adequate alpha-blockade for tachyarrhythmia; intraoperative handling of the tumour is minimal to avoid catecholamine surges.
- Conn syndrome: resistant hypertension with hypokalaemia and alkalosis, high aldosterone-to-renin ratio, adrenal vein sampling to lateralise when bilateral disease is possible; treated by unilateral adrenalectomy or mineralocorticoid antagonists.
- Adrenocortical carcinoma presents as a large heterogeneous, often hormone-secreting mass (Weiss criteria histologically) needing en bloc open resection; Cushing adenomas are excised unilaterally with perioperative steroid cover, since the contralateral axis is suppressed.
Common confusion
The classic error is operating on an unprepared phaeochromocytoma — a patient given a beta-blocker alone for tachycardia develops unopposed alpha-mediated hypertension and crisis. Another trap is assuming a small non-functioning lesion is harmless: even 'incidentalomas' need hormone testing, since a silent phaeochromocytoma can be lethal under anaesthesia. Conversely, stable, small, hormonally silent adenomas are simply followed with interval imaging.
Exam-focused takeaway
Questions pair tumour with test: metanephrines for phaeochromocytoma, dexamethasone suppression for cortisol, aldosterone-renin ratio for Conn; and pair tumour with operation or preparation (alpha before beta). The rule of 10s, the right adrenal vein-IVC relation, the 10 Hounsfield unit cut-off, and size thresholds of 4 and 6 cm recur. Stems describe episodic headaches with sweating and palpitations, or resistant hypertension with a low potassium, asking the diagnosis and the next step.
Frequently asked questions
What workup does every adrenal incidentaloma need?
Biochemical testing for cortisol, catecholamine and aldosterone excess, plus adrenal-protocol CT or MRI to characterise the mass.
Why must alpha-blockade precede beta-blockade in phaeochromocytoma?
Beta-blockade first leaves alpha-mediated vasoconstriction unopposed, precipitating hypertensive crisis; alpha-blockade with volume expansion first allows safe beta addition for rhythm control.
What is the rule of 10s in phaeochromocytoma?
A teaching mnemonic that about 10 per cent are bilateral, extra-adrenal, familial or malignant — modern series suggest some of these proportions are higher, so screen all patients genetically where feasible.
How is Conn syndrome confirmed and lateralised?
A raised plasma aldosterone-to-renin ratio confirms primary aldosteronism, and adrenal vein sampling lateralises a unilateral adenoma before adrenalectomy; otherwise medical antagonism with spironolactone or eplerenone.