What is the appropriate evaluation and management of an incidentally discovered left adrenal adenomatous hyperplasia in an adult patient with no known hormonal abnormalities?

Management of Left Adrenal Adenomatous Hyperplasia

For an incidentally discovered left adrenal adenomatous hyperplasia in an adult without known hormonal abnormalities, comprehensive biochemical screening is mandatory regardless of imaging characteristics, followed by size-based risk stratification to determine whether surgical intervention, surveillance, or no further follow-up is required. 1

Mandatory Hormonal Evaluation

All patients with adrenal masses ≥1 cm require complete biochemical screening, even when asymptomatic and imaging suggests benignity. 1, 2

Required Tests for Every Patient

• Perform a 1 mg overnight dexamethasone suppression test by administering 1 mg dexamethasone at 11 PM and measuring serum cortisol at 8 AM the next morning. 2, 3
  • Cortisol ≤50 nmol/L (1.8 μg/dL) excludes autonomous cortisol secretion
  • Cortisol 51-138 nmol/L (1.9-5.0 μg/dL) suggests possible autonomous cortisol secretion
  • Cortisol >138 nmol/L (>5.0 μg/dL) confirms autonomous cortisol secretion 2, 4

Conditional Hormonal Testing

• Screen for pheochromocytoma using plasma free metanephrines or 24-hour urinary fractionated metanephrines if the mass measures ≥10 Hounsfield Units (HU) on non-contrast CT or if symptoms of catecholamine excess are present (episodic hypertension, headaches, palpitations, diaphoresis, anxiety, tremor, pallor). 2, 5

• Screen for primary aldosteronism using the aldosterone-to-renin ratio if hypertension or unexplained hypokalemia is present; a ratio >20 ng/dL per ng/mL/hr indicates hyperaldosteronism and requires confirmatory saline suppression testing. 2, 5

• Measure serum androgens (DHEAS, testosterone) only if clinical signs of virilization or feminization are present or if adrenocortical carcinoma is suspected. 2

Imaging Characterization

Non-contrast CT is the mandatory first-line imaging modality for all adrenal lesions. 2, 5

• Lesions with attenuation ≤10 HU on non-contrast CT are lipid-rich adenomas with essentially 0% malignancy risk and require no further imaging characterization. 2, 6

• Lesions with attenuation >10 HU require secondary imaging—either contrast-enhanced CT with 10-15 minute delayed washout protocol or chemical-shift MRI—to further characterize the mass. 2, 5

• Enhancement washout >50% at 10-15 minutes strongly suggests a benign adenoma. 5

Size-Based Management Algorithm

Masses <3 cm

• Predominantly benign, but hormonal assessment remains obligatory. 1
• If imaging shows ≤10 HU and hormonal testing is negative, no further follow-up is required. 2, 3

Masses 3-5 cm

• Consider surgical removal if imaging is indeterminate (>10 HU with inadequate washout) or if functional activity is demonstrated. 1
• If radiologically benign (<10 HU) but ≥4 cm and non-functional, perform repeat imaging at 6-12 months. 2, 3

Masses >5 cm

• Surgical resection is warranted due to substantially increased malignancy risk (up to 25% for masses >6 cm). 1, 6

Follow-Up Recommendations

• No further imaging or hormonal testing is required for benign-appearing, non-functional adenomas <4 cm with CT attenuation ≤10 HU. 2, 3

• For radiologically benign lesions ≥4 cm, repeat imaging at 6-12 months; adrenalectomy is advised if growth exceeds 5 mm per year after reassessment of hormonal status. 2, 3

• Growth >5 mm/year mandates repeat functional work-up before considering surgical intervention. 3

Clinical History Targets

Look specifically for signs of hormone excess that may have been subclinical:

• Cortisol excess: weight gain, central obesity, moon facies, dorsocervical fat pad (buffalo hump), purple striae, easy bruising, proximal muscle weakness, hypertension, glucose intolerance, osteoporosis. 2, 5

• Aldosterone excess: resistant hypertension (requiring ≥3 antihypertensive medications), unexplained hypokalemia, muscle weakness, cramping. 2

• Catecholamine excess: episodic or sustained hypertension, headaches, palpitations, diaphoresis, anxiety, tremor, pallor. 2

When to Involve Multidisciplinary Team

Immediate consultation with endocrinology, surgery, and radiology is indicated when:

• Imaging is not consistent with a benign lesion (inhomogeneous, >20 HU, irregular borders)
• Evidence of hormone hypersecretion is confirmed
• Tumor growth exceeds 5 mm per year during surveillance
• Surgical intervention is being considered 2, 3

Critical Pitfalls to Avoid

• Never skip dexamethasone suppression testing, even in small, benign-appearing masses, as autonomous cortisol secretion occurs in 5.3% of incidentalomas and carries increased morbidity and mortality risk. 1, 5

• Never perform adrenal biopsy before excluding pheochromocytoma, as undiagnosed catecholamine excess can precipitate a fatal hypertensive crisis during the procedure. 3, 5

• Do not perform routine androgen testing unless virilization, feminization, or suspected adrenocortical carcinoma is present, as the yield is extremely low in asymptomatic patients. 5

• Hold interfering medications before testing when possible: beta-blockers, ACE inhibitors, and ARBs affect aldosterone/renin ratio; tricyclic antidepressants and decongestants affect metanephrine testing; estrogen and rifampin affect cortisol testing. 2