From the Guidelines
To determine if adrenal lesions are functionally active, a comprehensive work-up including a focused history and physical examination, measurement of hormone levels in blood and urine, and imaging studies such as CT or MRI should be performed, as recommended by the most recent guidelines 1.
Diagnostic Approach
The diagnostic approach to adrenal lesions should prioritize identifying signs and symptoms of adrenal hormone excess, adrenal malignancy, and/or extra-adrenal malignancy.
- A focused history and physical examination are crucial as the initial step in the work-up of an adrenal incidentaloma, as stated in the guidelines 1.
- Measurement of hormone levels in blood and urine, including plasma metanephrines, aldosterone-to-renin ratio, DHEA-S, and morning cortisol levels, can help detect excess production of these hormones.
- An overnight 1mg dexamethasone suppression test is particularly useful for detecting cortisol-producing adenomas, with normal suppression being below 1.8 μg/dL.
Imaging Studies
Imaging studies play a significant role in characterizing adrenal lesions.
- CT with contrast enhancement or MRI can assess for characteristics of active lesions, such as low lipid content (low attenuation on CT) or enhancement patterns.
- PET scans using specific tracers like 18F-FDG can identify metabolically active lesions.
- For indeterminate cases, adrenal vein sampling may be necessary to directly measure hormone production from each adrenal gland, as suggested in the guidelines 1.
Management
The management of adrenal lesions depends on their functional status and size.
- Functional adrenal lesions require specific treatment approaches based on the hormones they produce.
- Non-functioning lesions may simply need monitoring or intervention based on size and growth characteristics, with guidelines suggesting adrenalectomy for lesions growing >5 mm/year after repeating a functional work-up 1.
- The decision for adrenalectomy should be made after shared decision-making between patients and their clinicians, considering the risks and benefits of surgery versus monitoring, as emphasized in the guidelines 1.
From the Research
Determining Functional Activity of Adrenal Lesions
To determine if adrenal lesions are functionally active, several steps and considerations are involved:
- Imaging Techniques: The use of non-contrast CT, contrast-enhanced CT including delayed washout, and MR chemical shift analysis can help in characterizing adrenal lesions and assessing their functional activity 2.
- Hormonal Evaluation: Patients with adrenal incidentalomas should undergo hormonal evaluation for subclinical Cushing's syndrome and pheochromocytoma. Those with hypertension should also be evaluated for hyperaldosteronism 3.
- Biochemical Tests: Combined 1-mg dexamethasone suppression test, plasma metanephrines, and aldosterone/plasma renin activity measurements are reasonable initial hormonal evaluations 3.
- Size and Growth: Adrenal tumors with indeterminate radiological features that grow to at least 0.8 cm over 3-12 months may be considered for surgical resection 3.
- Multidisciplinary Approach: Management of patients with adrenal incidentalomas should involve a team of experienced surgeons, radiologists, and endocrinologists to determine the nature and functional status of the lesions 4.
Key Considerations
- The majority of adrenal incidentalomas are benign, but careful evaluation is necessary to identify primary adrenocortical carcinoma and functional adenomas 3.
- Radiological evaluation, including noncontrast and contrast computed tomography attenuation values, is crucial in differentiating between benign and malignant adrenal masses 3.
- Annual biochemical follow-up for up to 5 years may be reasonable for patients with adrenal incidentalomas, especially if the tumor is more than 3 cm in size 3.
- The assessment of risk of malignancy and hormonal activity guides the treatment strategy, which can range from simple follow-up to surgical resection 5.