What assessment and testing are necessary for a thickened left adrenal gland and a new lipomatous lesion in the right adrenal gland?

Assessment and Testing for Adrenal Lesions: Thickened Left Adrenal Gland and Right Adrenal Myelolipoma

For a thickened left adrenal gland and a new 8x9mm lipomatous lesion in the right adrenal gland (likely myelolipoma), comprehensive hormonal evaluation is required regardless of imaging characteristics, even for lesions that appear benign.

Hormonal Evaluation Required

• Cortisol excess screening:

  • 1mg overnight dexamethasone suppression test for all patients 1
  • Consider 24-hour urinary free cortisol and midnight salivary cortisol for additional confirmation 1

• Catecholamine excess screening:

  • Plasma free metanephrines or 24-hour urinary fractionated metanephrines
  • Values >2× upper limit of normal strongly suggest pheochromocytoma 1
  • This is particularly important before any surgical intervention is considered

• Aldosterone excess screening (if hypertension or hypokalemia present):

  • Aldosterone-to-renin ratio (ARR)
  • ARR >20 ng/dL per ng/mL/hr has >90% sensitivity/specificity for hyperaldosteronism 1

• Sex hormone evaluation (if clinical features suggest adrenocortical carcinoma):

  • DHEAS, testosterone
  • Consider 17β-estradiol, 17-OH progesterone, and androstenedione 1

Imaging Evaluation

For the thickened left adrenal gland:

• Determine Hounsfield Units (HU) on non-contrast CT
  • HU <10 indicates benign adenoma with 0% risk of adrenocortical carcinoma 1
  • Masses with HU >20 require further evaluation 1

For the right adrenal myelolipoma:

• Myelolipomas are typically benign lipomatous tumors 2
• Characteristic imaging features on CT include fat density components
• No additional imaging is typically needed if radiologic features are classic for myelolipoma 1

Management Approach

1. For the right adrenal myelolipoma (8x9mm):

   • Small myelolipomas (<4cm) with classic imaging features require no further follow-up imaging or functional testing 1
   • Myelolipomas are almost always benign 2

2. For the thickened left adrenal gland:

   • If <4cm with benign characteristics (HU ≤10) and non-functioning → no further follow-up needed 1
   • If ≥4cm or indeterminate features → repeat imaging in 6-12 months 1
   • Consider surgery if:
     • Size >4cm with inhomogeneous appearance or HU >20
     • Any hormone-producing tumor
     • Growth >5mm/year on follow-up imaging 1

Follow-up Recommendations

• For non-operated patients with non-functioning masses:
  • Consider repeat screening for pheochromocytoma and hypercortisolism at 1-2 years 1
  • Benign-appearing adenomas that remain unchanged do not require further follow-up 1

Important Caveats

• Endocrinologic evaluation must be done prior to any invasive procedure if there are signs of pheochromocytoma 3
• While myelolipomas are typically benign, rare cases of adrenocortical neoplasms with myelolipomatous metaplasia have been reported 4
• Some patients with conservatively managed adrenal lesions may develop hormonal hypersecretion during follow-up, emphasizing the need for appropriate surveillance 5

The presence of unchanged thickened left adrenal gland since 2018 suggests stability and likely benign nature, but hormonal evaluation remains essential to rule out subclinical hormone excess.