What are adrenal tumors, and what types of adrenal tumors are there?

Normally, the body's cells grow and divide to replace old or damaged cells. This growth is highly regulated, and once enough cells are produced to replace the old, normal cells stop dividing. Tumors occur when there is an error in this process, and cells continue to grow in an uncontrolled manner. Tumors can be benign or malignant. Although benign tumors may grow in an uncontrolled way, do not spread to other parts of the body (metastasis), or invade the surrounding tissues. Malignant tumors (also known as cancer) will grow without control, so that invade and damage other tissues around them. They also gain the ability to break from where you start and spread to other parts of the body, usually through the bloodstream or lymphatic system in the lymph nodes are found (a process known as metastasis).

The most common tumor of the adrenal gland is actually a benign tumor called adrenal adenoma. In most patients, these benign tumors do not cause a patient to have symptoms and do not need to be treated. They are usually found when a patient has a CT (or CAT) from the body for an unrelated reason, and are therefore sometimes called 'incidentalomas'. The most common malignant tumors found in the adrenal gland of tumors that originate from cancer cells that have metastasized (or spread) in other parts of the body to the adrenal gland through the bloodstream. There are different types of cancer can spread to the adrenal glands, most commonly melanomas, lung cancer and breast cancer. The adrenal glands are the fourth most common site in the body for cancer cells to metastasize to, after the lungs, liver and bones.

Cancers can arise directly from the adrenal glands, however, these are relatively rare. Cancers can arise directly from the adrenal cortex and are called adrenal cortical cancers. These cancers may be functioning (meaning they secrete excess steroid hormones) or non-functioning (meaning they do not secrete steroids). Functioning adrenal cortical cancers are more common than cancers that do not work. The cancer can also arise within the adrenal medulla, the most common of which are pheochromocytomas. In children, neuroblastoma tumors can develop within adrenal medulla. Pheochromocytomas and neuroblastomas was discussed elsewhere individually, will not be discussed further in this review.

Other types of adrenal cancers can occur, such as lymphoma, however, these cases are rare.