Adenoma: definition, cause, evolution, treatment

Adenoma tumor tyroid


An adenoma is a tumor that grows on a gland or organ. Generally benign, it nevertheless causes problems to be treated and must be monitored to avoid a cancerous development. For example: a prostate adenoma is an increase in the volume of the prostate; a colon or rectal adenoma is a benign tumor of the inner lining of the colon or rectum, lined with glands.

Definition: what is an adenoma?

An adenoma is a benign tumor developed in a gland (testicle, breast, kidney, thyroid, adrenal glands, pituitary gland, etc.) or certain glandular mucous membranes (colon, stomach, rectum, liver, uterus, etc.).

What causes an adenoma to appear?

They are not precisely known. “In some cases, such as colon adenomas, there is a genetic factor, explains Dr Monique Quillard, general practitioner. It is also thought that a diet too rich in animal protein and low in fiber would be responsible for colonic adenomas” .

What are the locations of the adenoma?

Adenoma has the particularity of copying the appearance and structure of the gland on or in which it develops. It is likely to reach all glands and mucous membranes and can therefore affect almost all organs. We thus speak of endocrine adenomas when it concerns the thyroid or the pituitary gland for example), of digestive adenoma when it concerns the stomach. Some are very common, such as prostate adenoma which affects more than one in two men over 55 or colon adenoma which affects 10% of people over 50. Others, like that of the liver, are rarer and cause no symptoms.

Prostate adenoma: symptoms and causes

It is very common since it affects nearly 60% of men between 55 and 70 years old. It is manifested by urinary symptoms such as a frequent need to urinate, day and night, difficulty in retaining, interruption of the urine stream, the feeling of not having completely emptied the bladder, urinary leakage as well as sexual disorders. These symptoms progress gradually. They are due to the compression of the urethra by the adenoma, hindering the emptying of the bladder. Complications: urinary tract infection, prostatitis, acute retention of urine.


It’s called a fibroadenoma. They are often very small and difficult to detect. Often there are no symptoms. Treatment may include a needle biopsy, and/or removal.


It is a benign endocrine tumor, developed in the pituitary which is a gland located at the base of the skull responsible for a wide variety of hormonal secretions. The disease is manifested by various disorders such as visual disturbances, headaches, dizziness, facial pain, fatigue and sleep disturbances. They can also be manifested by a hormonal imbalance (the pituitary gland being the “conductor” of the endocrine system), in the thyroid, ovaries, milk secretion, growth hormone secretion, but also diabetes, hypertension, depression, obesity.

We distinguish the anterior pituitary (endocrine gland) which secretes ACTH, FSH, LH, TSH, GH and prolactin, hormones essential to the proper functioning of the body, from the posterior pituitary which secretes ADH, responsible for diuresis (quantity of urine emitted).


It is a benign tumor of the parotid (salivary glands). The tumor located under the ear, slowly increases in volume over several years and will compress the facial nerve causing paralysis of the face. The diagnosis is confirmed by ultrasound. A puncture is necessary to make the differential diagnosis of adenoma or adenocarcinoma.


An adrenal adenoma affects an adrenal gland, that is to say located above the kidney. It is silent for a very long time, then causes hyper secretion of cortisol and therefore android-type obesity, arterial hypertension, great fatigue and genital insufficiency.

What is the diagnosis?

It is established according to the symptoms described by the patient and, when accessible, by palpation. For example, the essential examination in the event of suspicion of adenoma of the prostate remains the digital rectal examination performed with an empty bladder. An ultrasound or even an MRI can also be prescribed to determine the size of the tumour. Finally, a biopsy is often necessary to differentiate adenoma from adenocarcinoma (cCancer that forms in the glandular tissue).

What is the evolution of an adenoma?

Generally without danger, the adenoma can however be transformed into a cancerous tumor, that is to say into adenocarcinoma. The larger the adenoma, the higher the risk. Similarly, some people have multiple adenomas which, when located on the colon in particular, can degenerate into cancer. This is why if you have a family history of colon cancer, you should do colonoscopies from the age of 50.

Does the adenoma grow back?

Adenomatous polyps, about two thirds of colon polyps are adenomas – that means 66% of all colon polyps are precancerous! Adenomas are described by a growth pattern, or a microscopic description made by a pathologist to determine how often you need to return for a colonoscopy.

What percent of adenomas become cancer?

Tubular adenomas represent ~75% to 85% of adenomatous polyps and have a <5% chance of developing malignancy. Tubulovillous adenomas represent 10% to 15% of polyps and usually 20% to 25% contain malignancy. Villous adenomas account for 5% to 10% of remaining polyps and 35% to 40% of malignant polyps.

What are the treatments?

If it is small in size and does not affect the quality of life, no treatment is necessary. Medical supervision is essential.
In some cases, surgical removal of the adenoma as a preventive measure can be performed, during colonoscopy for example. This intervention is most often carried out under endoscopy when it comes to polyps residing on the mucous membranes (layers of cells lining the interior of the organs in contact with the air).

Can we cure it?

The adenoma can recur after surgical removal, essentially because there remain active cells in situ which will multiply again. At the level of the colon, other adenomas can develop in different places of the colon, this is the reason why it is necessary to regularly perform colonoscopies every 3 to 5 years depending on the case.

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Sources: PinterPandai, Wikipedia, Cleaveland Clinic, News Medical, Cancer, Harvard, Fight Colorectal Cancer, NCBI (National Center for Biotechnology Information) – U.S. National Library of Medicine, Healthline

Photo credit: Wikimedia Commons (Public Domain)

Photo description: image of adenoma on thyroid. Adenomas are benign tumors.

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