From the Guidelines
Adrenocortical carcinoma can be ruled out in incidental adrenal adenomas with suspected lung cancer using a combination of imaging and hormonal work-up tests.
Key Tests
- Imaging tests: CT or MRI of the abdomen and CT thorax to assess the size and characteristics of the adrenal mass, as well as to evaluate for potential metastases 1.
- Hormonal work-up:
- Glucocorticoid excess: dexamethasone suppression test, excretion of free urinary cortisol, basal cortisol, and basal ACTH 1.
- Sexual steroids and steroid precursors: DHEA-S, 17-OH-progesterone, androstenedione, testosterone, and 17-beta-estradiol (in men and postmenopausal women) 1.
- Mineralocorticoid excess: potassium, aldosterone/renin ratio (in patients with arterial hypertension and/or hypokalemia) 1.
- Catecholamine excess: normetanephrine, metanephrine, and methoxytyramine (plasma), or fractionated metanephrine excretion (24 h urine) 1.
Additional Tests
- FDG-PET: may be useful in distinguishing potentially malignant lesions from benign tumors in radiologically indeterminate adrenal lesions, particularly in patients with suspected pheochromocytoma or lung cancer 1.
- Adrenal biopsy: should be reserved for cases in which noninvasive techniques are equivocal, as it is almost never justified due to anticipated tumor spill 1.
Size and Malignancy Risk
- Size: is an important variable in predicting malignancy, with larger lesions (>5 cm) having a higher risk of malignancy, especially in patients with a history of malignancy 1.
- Lesions larger than 5 cm: should be removed due to the higher risk for malignancy 1.
From the Research
Diagnostic Tests for Adrenocortical Carcinoma
To rule out adrenocortical carcinoma in incidental adrenal adenomas with suspected lung cancer, several diagnostic tests can be employed. These include:
- Blood and urine tests to determine whether the tumor is functional or nonfunctional 2
- Imaging tests such as computed tomography (CT) scan or magnetic resonance imaging (MRI) 2
- Unenhanced CT attenuation values expressed in Hounsfield units to differentiate between benign and malignant adrenal masses 3, 4, 5
- 1-mg dexamethasone suppression test to evaluate for subclinical Cushing's syndrome 3, 4, 5
- Plasma metanephrines and aldosterone/plasma renin activity measurements to evaluate for pheochromocytoma and hyperaldosteronism 3, 4, 5
Radiological Evaluation
Radiological evaluation is crucial in differentiating between benign and malignant adrenal masses. The following radiological features can indicate malignancy:
- Noncontrast attenuation value of more than 10 Hounsfield units 4, 5
- Inhomogeneous lesions 4
- Lesions larger than 4 cm in size 3, 4
- Lesions with suspicious radiological findings 3
Hormonal Evaluation
Hormonal evaluation is essential to exclude hormone-excess disorders. The following tests can be used: