Adrenal metastases of malignant melanoma: characteristic computed tomography appearances

Malignant melanoma is an extremely aggressive form of cancer. Adrenal metastases are found in 50% of cases of malignant melanoma, and are most often clinically and biochemically silent. Clinical presentation varies, and the diagnosis of adrenal metastases is often made incidentally, and frequently years after treatment of the primary lesion. An adrenal mass lesion seen on a CT scan, greater than 5 cm in diameter, with central or irregular areas of necrosis/haemorrhage (and no lipomatous component) is characteristic of a metastasis from malignant melanoma, in the setting of normal gland function. If these features are bilateral, they are pathognomonic. Oval, low-attenuation (on CT) adrenal masses less than 3 cm in diameter should not be considered benign in a patient with any prior history of melanoma. Careful imaging review of the adrenal glands should be undertaken in all patients with malignant melanoma. Early diagnosis of these distant metastases has important prognostic and therapeutic implications. The four cases presented illustrate the spectrum of presentations and clinical course of adrenal metastases from malignant melanoma. The accompanying CT images show the characteristic appearances of adrenal metastases.