How is an incidental adrenal lesion diagnosed?

Information must be obtained to form an assessment of the nature of the lesion as this guides further treatment. For example, functioning lesions (other than Congenital Adrenal Hyperplasia) can be treated by surgery. This information comes from several sources, namely;

How big is the tumour?

The larger the tumour the more likely it is that it is malignant. As most are metastases from a distant primary tumour, a search for the primary tumour is necessary.

Is there evidence of hormone excess or deficiency?

Evidence for any hormone abnormality comes from an assessment of physical features, the patient's history and from any necessary blood and urine tests.

What is the appearance of the tumour on imaging?

Invasion of adjacent structures indicates malignancy. Other tumours such as the myelolipoma have characteristic CT images allowing good identification. The experience of the radiologist is called upon here.

Fine needle aspiration (using a needle to extract a few cells from the mass to determine what it is) can then be used for lesions about which diagnosis is not confident, especially for unilateral lesions which are more likely to be primary malignancies or metastases than bilateral lesions.