From the Guidelines
The work-up for bilateral adrenal hyperplasia with an 8 mm fatty density lesion should begin with biochemical testing to determine if the adrenal lesions are functioning or non-functioning, as recommended by the most recent guidelines 1.
Initial Evaluation
Initial tests should include:
- A 1 mg overnight dexamethasone suppression test to screen for cortisol excess
- Plasma metanephrines or 24-hour urinary metanephrines to rule out pheochromocytoma
- Plasma aldosterone to renin ratio if hypertension is present to evaluate for primary aldosteronism Given the small size (8 mm) and fatty density characteristics, this lesion is most likely an adrenal adenoma, which has benign features, as supported by the guidelines 1.
Imaging Characteristics
Lesions smaller than 1 cm with Hounsfield units less than 10 on unenhanced CT are typically benign adenomas and do not require surgical intervention, according to the guidelines 1.
Management
If biochemical testing reveals the lesion is non-functioning, follow-up imaging in 6-12 months is recommended to ensure stability 1. However, if hormonal excess is detected, referral to an endocrinologist is necessary for management, which may include medical therapy or, in some cases, adrenalectomy.
Underlying Endocrine Disorder
The presence of bilateral hyperplasia suggests a possible underlying endocrine disorder, such as congenital adrenal hyperplasia, Cushing's disease, or primary hyperaldosteronism, which would require specific treatment based on the identified condition, as discussed in the guidelines 1.
Multidisciplinary Review
There should be a low threshold for a multidisciplinary review by endocrinologists, surgeons, and radiologists when the imaging is not consistent with a benign lesion, there is evidence of hormone hypersecretion, the tumor has grown significantly during follow-up imaging, or adrenal surgery is being considered 1.
From the Research
Work-up for Bilateral Adrenal Hyperplasia
The work-up for bilateral adrenal hyperplasia involves a comprehensive approach, including clinical history, physical examination, dynamic hormone evaluation, and imaging modalities 2.
Imaging Characteristics
Imaging characteristics of each lesion are crucial in determining the etiology of bilateral adrenal masses. For example, a 8 mm fatty density lesion may suggest a myelolipoma, which is a type of benign tumor that can occur in the adrenal glands 3.
Hormonal Evaluation
Hormonal evaluation is essential in cases of bilateral adrenal hyperplasia, including testing for primary aldosteronism, pheochromocytoma, and evaluation for autonomous cortisol secretion 4. The 1 mg overnight dexamethasone suppression test can aid in establishing the degree of cortisol excess.
Key Considerations
Key considerations in the work-up for bilateral adrenal hyperplasia include:
- Assessment of clinical history and physical examination
- Dynamic hormone evaluation
- Imaging modalities to determine the key radiographic features of each adrenal nodule
- Consideration of familial syndromes
- Evaluation for autonomous cortisol secretion and primary aldosteronism
Management
The management of bilateral adrenal hyperplasia remains controversial, and treatment options should be considered individually 5, 4. Bilateral adrenalectomy may be reserved for patients with severe Cushing's syndrome, while unilateral adrenalectomy may be considered in selected patients. Medical therapy may be an option in cases where the regulation of cortisol secretion is mediated by aberrant receptors.
Diagnostic Approach
The diagnostic approach for primary bilateral macronodular adrenal hyperplasia (PBMAH) consists of both imaging and hormonal characterization, with imaging characterization done separately for each lesion 4. The European Society of Endocrinology and the European Network for the Study of Adrenal Tumors have updated guidelines, introducing a 4-option schema based on imaging, aiding in targeted hormonal testing and management 6.