Also referred to as an adenomatous polyp, an adenoma is a small and typically harmless tumor that can develop in the glandular tissue of multiple organs throughout the body, including the:
- Pituitary gland
- Thyroid gland
- Adrenal glands
Less commonly, adenomas may occur in the appendix, liver or lungs. An adenoma itself is not cancerous, although some adenomas may be pre-cancerous and eventually grow into cancer if they are not surgically removed. An adenoma that becomes cancerous is known as an adenocarcinoma.
An adenoma occurs when cells in glandular tissue fail to follow normal lifespans and instead continue to divide. This unusual cell division is the cause of both adenomas and cancerous tumors, although adenomas tend to grow more slowly and are less aggressive than cancer.
What exactly causes an adenoma is not clear. However, adenomas are very common—for instance, the National Institutes of Health estimates that colorectal adenomas occur in 30% of Americans over the age of 50.
Most adenomas don’t cause noticeable symptoms, although this depends on where they are located in the body. Thyroid adenomas (often referred to as nodules) may secrete hormones that lead to weight loss, tremors and irregular heartbeat. When adenomas develop on the adrenal glands above the kidneys, a variety of symptoms such as bruising easily, weakness, weight gain and high blood pressure can occur.
Adenomas most commonly grow in the colon (large intestine). Many people with colon adenomas—known as polyps—don’t have noticeable symptoms, although some polyps may cause:
- Abdominal pain
- Blood in stool
- Rectal bleeding
- Changes in bowel habits
Imaging procedures are typically used to differentiate adenomas from cancerous tumors. Colon polyps can be identified through a colonoscopy or sigmoidoscopy, while thyroid and breast adenomas can be observed during an ultrasound. A biopsy to collect a small amount of the adenoma and test it under a microscope for cancerous cells may also performed.
Tampa General Hospital’s Cancer Institute provides comprehensive surveillance and treatment for adenomas located throughout the body. The most common treatment approach for colon polyps is surgical removal, although a “watchful waiting” approach may be appropriate for asymptomatic patients who have adenomas in other organs.