Adrenal metastases

Overview
Newer imaging technologies such as CT and MRI now indicate that the adrenal is a common site of metastases, and that adrenal metastases occur much more frequently than realized.

Epidemiology and Demographics
The primary tumor is a major determinant of the frequency of adrenal metastases. Primary tumors that frequently metasticize to the adrenal include:
 * 1) 50% of melanomas metastasize to the adrenals
 * 2) 30-40% of breast and lung cancers
 * 3) 10-20% of renal and gastrointestinal tumors

The most common sites for a primary tumor to metastasize to are
 * 1) Lung
 * 2) Liver
 * 3) Bone
 * 4) Adrenal gland

Screening
If adrenal metastases are present on an initial imaging survey, then this indicates that stage IV disease is present. This is critical, because the presence of adrenal metastases changes the choice of treatment in most case. The only except is ipsilateral renal cancer.

Pathophysiology & Etiology
Metastases are non calcified, vary in size and may be unilateral or bilateral. One complication of adrenal metastases is central necrosis with adrenal hemorrhage.

History and Symptoms
Adrenal metastases are most often asymptomatic. In the event of extensive bilateral metastatic disease, signs and symptoms of adrenal insufficiency may be present which include:

Dizziness

Faintness

Fatigue

Weakness

Weight loss

Physical Examination
Usually non-revealing

MRI and CT
CT is first line imaging tool to screen the adrenal glands if a primary malignancy with a high for adrenal metastases (melanoma, lung cancer, and breast cancer) is present.

MRI and ultrasound are of limited use in the first line screening and evaluation of adrenal metastases.

PET
Positron emission tomography (PET) may demonstrate lower metabolic activity in an incidental adrenal adenoma vs a metastasis which may be more metabolically active.