Adrenal Cortex Tumors and Hyperplasias

Abstract

The adrenal cortex tumors include both malignant adrenal cortex cancers (ACC) and benign masses (ACT) that can be either secreting, of one of the hormones normally produced in the adrenal cortex (Cushing’s syndrome if the hypersecretion is of cortisol or Conn’s syndrome if it is aldosterone) or non-secretory (Incidentalomas). The outer part of the adrenal glands, the adrenal cortex, is responsible for regulating important body functions including blood sugar levels, body water and salt levels, and consequently blood pressure and kidney functions, the immune system, the inflammatory response, the physiological response to stress, and, finally, sexual and reproductive functions. The three different parts of the adrenal cortex, zona glomerulosa, zona fasciculata and zona reticularis, are responsible for producing different hormones namely mineralocorticoids, glucocorticoids, and androgens (and eventually also estrogens). The glomerulosa secretes aldosterone, and gives rise to Primary Aldosteronism (PA)/Hyperaldosteronism that can result either from an adenoma (Conn’s syndrome) or from bilateral hyperplasia (BAH). The zona fasciculata secretes cortisol and adenomas that produce this hormone are associated to a distinct syndrome called Cushing’s syndrome. Finally the adrenal cortex reticularis zone is supposed to produce adrenal androgens (namely dehydroepiandrosterone – DHEA and dehydroepiandrosterone sulfate – DHEA-s) that can in turn be either converted into testosterone or aromatized to estrogen in peripheral organs like the adipose tissue. In spite of the fact that normally this peripheral conversion is more important than the local production, there are adrenal cortex tumors that can produce testosterone directly, the Androgen-secreting tumors as well as adrenocortical carcinomas expressing aromatase and producing estrogens, the Estrogen-secreting tumors. The majority of adrenocortical tumors (ACT) are benign and silent (non-secreting adenomas or incidentalomas) since they do not ever result in hormone secretion. Its true incidence is still unknown because it is probable that many of these cases still go undiagnosed. However, it is estimated that they are present in at least 3% of the adult population (especially over 50 years of age) (National Institutes of Health, 2002; Grumbach et al., 2003). Most of these tumors are discovered incidentally due to the widespread availability of imaging studies for intra-abdominal diseases. This is the reason why they are designated as Incidentalomas.