What is the management approach for a small adrenal adenoma measuring 2.2 cm?

Management of a Small Adrenal Adenoma Measuring 2.2 cm

For a small adrenal adenoma measuring 2.2 cm without a history of malignancy, observation with no further follow-up imaging or functional testing is recommended, as most small (<3 cm) incidentally discovered adrenal masses are benign and extensive workup is not justified. 1

Initial Evaluation

• Adrenal adenomas measuring less than 3 cm have a very low risk of malignancy and are typically benign 1
• Before concluding observation is appropriate, confirm the lesion has benign imaging characteristics:
  • Homogeneous appearance
  • Well-defined margins
  • Low attenuation (<10 Hounsfield Units) on non-contrast CT 1
• If the lesion has attenuation >10 HU on non-contrast CT, second-line imaging with either washout CT or chemical shift MRI should be performed to confirm benign nature 1

Functional Assessment

• Despite benign radiographic appearance, all adrenal incidentalomas should undergo hormonal evaluation to exclude subclinical hormone production 1
• Recommended screening tests include:
  • Plasma aldosterone and renin activity (for hyperaldosteronism) 1
  • Overnight 1 mg dexamethasone suppression test or midnight salivary cortisol (for Cushing syndrome) 1
  • Plasma-free metanephrines or 24-hour urinary metanephrines (for pheochromocytoma) 1

Management Algorithm

1. For non-functioning adenomas <3 cm with benign imaging characteristics:

   • No further follow-up imaging or functional testing is required 1

2. For functioning adenomas (regardless of size):

   • Cortisol-secreting adenoma: Laparoscopic adrenalectomy is recommended 1
   • Aldosterone-secreting adenoma: Laparoscopic adrenalectomy is recommended 1
   • Pheochromocytoma: Adrenalectomy after appropriate alpha-blockade 1

3. For adenomas with atypical features but <4 cm:

   • Consider repeat imaging in 6-12 months to assess for growth 1
   • Growth rate >3 mm/year raises concern for malignancy 2

Important Considerations

• The risk of primary adrenal cortical carcinoma in patients with adrenal masses is approximately 4.7%, but much lower for masses <3 cm 1
• Growth pattern is an important indicator of malignancy - benign adenomas either don't grow or grow slowly (<3 mm/year), while malignant lesions typically grow >5 mm/year 2
• Adrenal biopsy should be reserved only for cases where noninvasive techniques are equivocal and there is high suspicion for metastatic disease 1

Common Pitfalls to Avoid

• Overdiagnosis and overtreatment of small adrenal adenomas can lead to unnecessary procedures and patient anxiety 1
• Failure to perform hormonal evaluation may miss subclinical hormone production, which occurs in approximately 5% of incidentalomas 1
• Relying solely on size without considering imaging characteristics may lead to unnecessary follow-up for clearly benign lesions 1

Special Situations

• In patients with a history of malignancy, even small adrenal lesions warrant closer evaluation as the risk of metastatic disease is significantly higher (25-72% depending on primary tumor type) 1
• For patients with bilateral adrenal adenomas, consider nodular hyperplasia which may require different management approaches 3