What hormone tests are recommended for adrenal myelolipoma?

Hormone Tests for Adrenal Myelolipoma

For adrenal myelolipoma, a comprehensive hormonal evaluation should be performed even though most are non-functioning, as some may be associated with hormone excess. 1

Initial Evaluation

Recommended Hormone Tests:

1. Glucocorticoid Excess Assessment

   • 1 mg overnight dexamethasone suppression test (primary screening test) 1
   • Serum cortisol (morning baseline) 1
   • 24-hour urinary free cortisol 1
   • Plasma ACTH 1

2. Mineralocorticoid Excess Assessment (if hypertension or hypokalemia present)

   • Serum potassium 1
   • Aldosterone-to-renin ratio 1

3. Catecholamine Excess Assessment (if HU ≥10 on non-contrast CT or symptoms present)

   • Plasma free metanephrines (preferred first-line test) 1, 2
   • Alternatively: 24-hour urinary fractionated metanephrines 1, 2

4. Sex Hormone and Steroid Precursor Assessment

   • DHEA-S (serum) 1
   • Testosterone (serum) 1
   • 17-OH-progesterone (serum) 1
   • Androstenedione (serum) 1
   • 17-beta-estradiol (serum, only in men and postmenopausal women) 1

Testing Algorithm

Step 1: Initial Screening

• All patients with adrenal myelolipoma should undergo screening for autonomous cortisol secretion with 1 mg dexamethasone suppression test 1
• Interpretation:
  • <50 nmol/L excludes cortisol hypersecretion
  • 51-138 nmol/L suggests possible autonomous cortisol secretion

  • 138 nmol/L indicates cortisol hypersecretion

Step 2: Targeted Testing Based on Clinical Presentation

• If hypertension or hypokalemia present:

  • Perform aldosterone-to-renin ratio testing 1
  • Optimal collection: morning, after patient has been upright for 2 hours and seated for 5-15 minutes
  • Ensure patient is potassium-replete and off interfering medications

• If HU ≥10 on non-contrast CT or symptoms of catecholamine excess:

  • Perform plasma free metanephrines testing 1, 2
  • Collect after patient has been lying supine for 30 minutes

• If signs of virilization or suspected adrenocortical carcinoma:

  • Perform sex hormone and steroid precursor testing 1

Special Considerations for Myelolipomas

While most adrenal myelolipomas are non-functioning, there are important exceptions:

• Some myelolipomas may be associated with congenital adrenal hyperplasia 3
• Cases of hormone-secreting myelolipomas have been reported, including:
  • Cortisol and aldosterone co-secretion 4
  • DHEA-S overproduction 5
  • Primary aldosteronism 5

Follow-up Testing

• Patients with benign non-functional myelolipomas containing macroscopic fat detected on initial imaging do not require further follow-up imaging or functional testing 1
• If hormone excess is detected, appropriate management should be pursued, potentially including surgical intervention

Common Pitfalls to Avoid

1. Assuming all myelolipomas are non-functional - While most are non-functioning, some can be associated with hormone excess 4, 5

2. Inadequate preparation for hormone testing:

   • Failing to control for medications that interfere with aldosterone/renin testing
   • Not collecting plasma metanephrines after appropriate rest period
   • Improper timing for cortisol measurements

3. Missing concomitant adrenal pathology - Myelolipomas can coexist with other adrenal lesions such as adenomas 5

4. Overlooking subclinical hormone excess - Even subtle hormone abnormalities may have clinical significance and should be evaluated 6