Adrenal Adenoma Cushing's Syndrome Diagnosis and Management

Initial Screening and Diagnosis

The Endocrine Society recommends that all patients with suspected adrenal adenoma Cushing's syndrome should undergo a 1 mg overnight dexamethasone suppression test, with serum cortisol measured at 8 AM the next morning after administering 1 mg dexamethasone at 11 PM 1
Interpretation of dexamethasone suppression test results: serum cortisol ≤50 nmol/L (1.8 μg/dL) excludes autonomous cortisol secretion, serum cortisol 51-138 nmol/L (1.9-5.0 μg/dL) suggests possible autonomous cortisol secretion, and serum cortisol >138 nmol/L (>5.0 μg/dL) indicates evidence of autonomous cortisol secretion 1
Plasma ACTH levels should be measured to differentiate between ACTH-dependent and ACTH-independent Cushing's syndrome; low or undetectable ACTH levels suggest an adrenal source 2

Non-contrast CT is the first-line imaging modality to characterize adrenal masses, with benign features including homogeneous, well-circumscribed appearance, <10 Hounsfield Units (HU) on non-contrast CT, and size <4 cm 1, 2, 3
For indeterminate masses on non-contrast CT, second-line imaging should be performed, including washout CT protocol and chemical-shift MRI 1, 2

Unilateral cortisol-secreting adrenal masses with clinically apparent Cushing's syndrome should undergo unilateral adrenalectomy, as recommended by the American Urological Association 4
For mild autonomous cortisol secretion (MACS), consider adrenalectomy for younger patients with progressive metabolic comorbidities attributable to cortisol excess, and perform annual clinical screening for new or worsening associated comorbidities 4
Minimally invasive surgery (laparoscopic/robotic adrenalectomy) should be performed when feasible, as recommended by the American Urological Association 4, 5

Preoperative management must include treatment of comorbid conditions such as diabetes and hypertension, as recommended by the American Urological Association 6
Intraoperative planning should include special attention to prophylactic antibiotics, as recommended by the American Urological Association 6

After resection of cortisol-secreting adenomas, patients should be monitored for resolution of hypercortisolism, improvement in comorbid conditions, and potential recurrence (estimated at around 10% in the original adrenal gland and up to 30% in the contralateral gland), as recommended by the American Urological Association 2, 6
Lifelong monitoring is necessary due to the significant risk of recurrence, as recommended by the American Urological Association 6

Do not rely solely on radiological appearance to predict hormone secretion status, as recommended by the Endocrine Society 2
Do not perform adrenal mass biopsy without excluding pheochromocytoma, as this can trigger life-threatening hypertensive crisis, as recommended by the Endocrine Society 2
Avoid unnecessary repeated imaging for small adrenal masses with benign characteristics, as recommended by the Endocrine Society 3