The adrenal glands (or adrenals) are two small triangular structures “resting” on the kidneys and responsible for the production of several hormones critical for metabolic and hydroelectrolyte balance and stress response, in accordance with signals from the brain (hypothalamic-pituitary-adrenal axis).
Tumors of the adrenal glands are a group of neoplasms that can arise primarily within the glands themselves (adrenal adenoma) and be mostly benign or form as distant metastases of tumors with primary sites in other organs (in particular, lung and breast).
Primary malignant tumors of the adrenal glands are very rare.
In all cases, the tumor may affect the cortical (outermost) part of the adrenal gland or the medullary (innermost) part.
In the former case, the tumor may be of the “secreting” type, i.e., resulting in excessive production of one of the hormones normally produced by the adrenal gland, or of the “non-secreting” type.
In the second case, the tumor is called “pheochromocytoma,” as it is determined by the uncontrolled growth of a subset of cells in the adrenal medulla called chromaffin cells, and is always secreting, resulting in excessive production of adrenaline and noradrenaline.
