An adenoma is a generally benign growth that can appear on several structures and organs, particularly the colon, kidneys, adrenal gland, thyroid gland, pituitary gland, liver, the breasts, or the appendix.
Most adenomas are harmless, but are generally removed as a matter of course as they can often become malignant or produce hormones in larger than normal quantities. For example:
- They can become malignant and cancerous (an adenocarcinoma)
- They can produce hormones without any prompting from other hormones, leading to paraneoplastic syndrome
- A malignant adenoma on the adrenal gland can cause Cushing's syndrome
- They can become large enough to press against other organs in the body, interfering with their function.
Some of the examples shown in House (TV series) are:
- In Heavy, an adrenal adenoma causes Cushing's syndrome
- In Acceptance, a small adenoma of the adrenal gland (a pheochromocytoma) often causes the patient to experience extreme anxiety and rage.
- In TB or Not TB, a small adenoma on the pancreas (a nesidioblastoma) causes the sudden release of insulin, rapidly resulting in low blood sugar.
- In Daddy's Boy, an adenoma on the spine (a cavernous angioma) results in the patient feeling shocks.
- In Spin, an adenoma on the thyroid gland (a thymoma) results in many of the patient's symptoms.
- In The Mistake, House realizes the main patient's brother has an adenoma on his liver (a hepatocellular carcinoma) that has also been transferred to the patient by transplant, resulting in cancer.
- Another hepatocellular carcinoma is seen in the patient in Need to Know, the result of mixing fertility medications with the pill.