Adrenal Cancer

Excerpt

The adrenal is an endocrine organ that has two physiological functions. The outer adrenal cortex produces steroid hormones, including glucocorticoids such as cortisol, and mineralocorticoids (aldosterone, and the androgen dehydroepiandrosterone. The glucocorticoids play a role in carbohydrate, protein, and fat metabolism. The mineralocorticoids are essential for the sodium (Na) and potassium (K) balance and the maintenance of fluid homeostasis. Glucocorticoids and mineralocorticoids are critical for survival. The inner adrenal medulla produces catecholamines (dopamine, epinephrine, and norepinephrine ).

Occasionally one does encounter adrenal masses during a routine study. These lesions can categorize as either functional (hormone-secreting) or silent (either benign or malignant). Overall, less than 1% of these tumors are cancerous.

The Fourth Edition of the World Health Organization (WHO) classification of endocrine tumors published in 2017 has classified adrenal cancer in two groups. The first includes tumors of the adrenal cortex, and the second group includes tumors of the adrenal medulla and extra-adrenal paraganglia. The key feature of the WHO classification is the role of genetics that may be involved in adrenal cortical carcinoma and pheochromocytoma/ paraganglioma as well as the inclusion of a few rare malignancies of the adrenal cortex and medulla.

The following are tumors of the adrenal cortex:

1. Cortical carcinoma

2. Cortical adenoma

3. Sex cord-stromal tumors

   1. Granulosa cell tumor

   2. Leydig cell tumor

4. Adenomatoid tumor

5. Mesenchymal and stromal tumors

   1. Myelolipoma

   2. Schwannoma

6. Hematological tumors

7. Secondary tumors

Adrenocortical adenoma (ACA), Adrenal myelolipoma (mesenchymal and stromal tumors) and adrenal adenomatoid tumor are benign neoplasms of the adrenal cortex. The sex cord-stromal tumor of the adrenal gland is rare, and there are only six reports in the literature. Primary hematological tumors are mostly lymphomas and rarely plasmacytoma. Secondary tumors of the adrenal cortex are usually metastatic lesions due to direct infiltration by adjacent cancer or more commonly via hematogenous spread from a distant site. Adrenal metastases are common in patients with advanced cancer.

Adrenocortical carcinomas (ACC) are very uncommon; these lesions are less common than cortical adenomas and pheochromocytoma. The worldwide incidence of ACC is 0.5 to 2 per 1 million people annually. However, this neoplasia accounts for 0.02 to 0.2% of all cancer-related deaths. Adrenocortical carcinomas are very aggressive lesions and in some cases may be functional and present with Cushing syndrome and/or virilization. In most cases, ACC is non-functional and presents as an abdominal mass or an incidental finding.

As with all adrenal tumors, the presence of local or distant spread defines their malignancy. No absolute criteria of malignancy exist for lesions confined to the adrenal gland, but a Weiss score of 3 or higher, which is determined by histopathological features, is generally an indicator of malignancy.