The presentation may depend on the site:

• Pituitary: Microadenoams may will be asymptomatic, but macroadenomas will cause symptoms due to their mass effect on structures around it. There may be headache and if the adenoma is big enough it may compress the optic chiasma causing visual field loss. Other clinical aspects will depend if the adenoma is secreting hormones such as growth hormone, which may lead to a clinical syndrome called acromegaly [7].
• Colon: Most colonic polyps are be asymptomatic. The most common symptom being rectal bleeding. Constipation or diarrhea may occur.
• Adrenal: The symptoms are dependent on the hormone that is being secreted, if any at all. In case of pheochromocytoma, then symptoms that are adrenergic should be sought. Other hormones such as aldosterone may present with electrolyte imbalance symptoms. Corticosteroid excess will present with Cushing syndrome.
• Thyroid: About 10% of people have an isolated thyroid nodule. Most will be asymptomatic and may present with pressure symptoms only if it is large enough. The few that secrete hormones will have symptoms of hyperthyroidism such as weight loss, irritability, heat intolerance and cardiac rhythm abnormalities like atrial fibrillation.
• Parathyroid: These may secrete parathyroid hormone and cause primary hyperparathyroidism which will present with symptoms of calcium excess. The clinical syndrome will present with the classic bones, stones, abdominal groans and psychic moans [8] [9] [10].

• Pain

  Center: Sessile, centrally depressed polyp in the descending duodenum of a 64 year-old woman undergoing endoscopy for evaluation of abdominal pain. The lesion was a benign adenoma on biopsy. [endoatlas.com]

  These tumors vary in their behavior, from locally aggressive to blatantly malignant, and are sometimes associated with pain or tenderness. [parotidsurgerymd.com]

  Pancreas: pain in the abdomen, diarrhea, stomach pain, persistent fatigue, fainting, and weight gain can indicate one of the various types of pancreatic adenomas or pancreatic cancer. [encyclopedia.com]

  A 48 years old male patient admitted to the gastroenterology clinic due to the epigastric pain spreading dorsally. No significant feature is present in his clinical history. [ncbi.nlm.nih.gov]

• Asymptomatic

  Mediendatei abspielen Asymptomatic-papillary-fibroelastoma-of-the-Aortic-valve-in-a-young-woman---a-case-report-1476-7120-7-43-S1.ogv 0,9 s, 636 × 432; 241 KB Mediendatei abspielen Asymptomatic-papillary-fibroelastoma-of-the-Aortic-valve-in-a-young-woman [commons.wikimedia.org]

  Most will be asymptomatic and may present with pressure symptoms only if it is large enough. [symptoma.com]

  Patients with focal nodular hyperplasia are usually asymptomatic and rarely experience complications. [ncbi.nlm.nih.gov]

  Most patients with HA are asymptomatic and lesions are found incidentally during laparotomy or radiologic studies performed for other reasons. [orpha.net]

• Weakness

  A 54-year-old woman who presented with bone pain and muscle weakness for 2 years was clinically suspected of having tumor-induced osteomalacia. A Ga-DOTANOC PET/CT was performed for localization of the causative tumor. [ncbi.nlm.nih.gov]

  Pseudo-invasive adenomatous polyps result from trauma and prolapse of adenomatous epithelium in areas of defective or weak muscularis mucosae into their stalk.1 They are rare lesions and may be unfamiliar to some endoscopists.2 The distinction between [elsevier.es]

  Other complications are less common, but may include: Nephrocalcinosis (calcium deposits in the kidneys that can reduce kidney function) Osteitis fibrosa cystica (softened, weak areas in the bones) Complications from surgery include: Damage to a nerve [nlm.nih.gov]

• Swelling

  After rinsing, there is still a slight mucous, yellowish residue over a swelling (Fig. 1a). On a closer top view, the polyp becomes clearer (Fig. 1b), and after full suctioning it then appears all the more clearly as a glassy swelling (Fig. 1c). [endoscopy-campus.com]

  Swelling सूजन, अंड वृध्दि, फुलाव, उभाड़, उन्नतोदर, गिलटी, Wasp things cause swelling and sharp pain / An aneurysm is an abnormal swelling or bulge in the wall of a blood vessel such as an artery. [studysite.org]

  Sixty years old farmer presented with painless swelling in the upper lip for the last 8 years. History revealed recurrent mass in the midline of upper lip with no other complaints. He was operated 3 times for this complaint in the past. [ncbi.nlm.nih.gov]

  The tumors usually cause a firm, painless swelling in one of the salivary glands, and the size of the swelling gradually increases. [parotidsurgerymd.com]

  The skin over the swelling appeared normal and was pinchable with no localized increase in temperature. [ijdr.in]

• Anemia

  Due to the fact that clinically and paraclinically this tumor presented certain features of malignancy, such as weight loss, intestinal transit disorders, anemia, and the 2 hyperechoic hepatic lesions which could suggest liver metastases, we performed [journals.lww.com]

  […] degradation by APC (J Gastroenterol Hepatol 2012;27:1423) Diagrams / tables Images hosted on other servers: Wnt/β-catenin pathway Clinical features <1 cm: usually asymptomatic and detected by screening colonoscopy >1 cm: may bleed, lead to iron deficiency anemia [pathologyoutlines.com]

  If symptoms develop, they can include: changes in bowel habits, such as mucus in the stool bleeding from the rectum anemia fatigue Diagnosis If you have symptoms or your doctor thinks you might have adenomas, you will be sent for tests. [cancer.ca]

  Anemia, fatigue, lethargy, menstrual disorders, libido and sexual disorders, constipation or symptoms of hypothyroidism (underactive thyroid) can also occur. [ims.uniklinik-freiburg.de]

  But you may notice: Bleeding in your bottom Mucus in your poop Frequent diarrhea or constipation Belly cramps Anemia, from losing blood in your poop Continued Diagnosis During a colonoscopy, your doctor inserts a long, flexible tube with a lens into your [webmd.com]

• Nausea

  Symptoms may include headache, nausea, visual loss, double vision and confusion. Most patients have undiagnosed hormone insufficiency prior to the apoplectic event. Pituitary Apoplexy is best confirmed by MRI. [brain-tumor.org]

  Symptoms may include: Headache Nausea Visual loss Double vision Confusion Most patients have undiagnosed hormone insufficiency prior to the apoplectic event. Pituitary apoplexy is best confirmed by MRI. [pacificneuroscienceinstitute.org]

  These might include: mental changes such as depression, lethargy, or confusion nausea vomiting pain in your muscles or abdomen Sometimes, doctors aren’t sure what causes a tumor to appear on one of your glands. [healthline.com]

  Symptoms may include any of the following: Confusion Constipation Lack of energy ( lethargy ) Muscle pain Nausea or decreased appetite Urinating more often at night Weak bones or fractures Blood tests may be done to check levels of: PTH Calcium Phosphorus [nlm.nih.gov]

• Vomiting

  These might include: mental changes such as depression, lethargy, or confusion nausea vomiting pain in your muscles or abdomen Sometimes, doctors aren’t sure what causes a tumor to appear on one of your glands. [healthline.com]

  (ACTH), which triggers the adrenal glands to make steroid hormones Hyperthyroidism from too much thyroid stimulating hormone (TSH) Some general symptoms of pituitary adenomas include: Headaches Vision problems (double vision, vision loss) Nausea or vomiting [my.clevelandclinic.org]

  Occasionally, however, they move to the chest, along with the thymus. 1 Most patients with hyperparathyroidism are asymptomatic, but any symptoms that do appear are generally caused by hypercalcemia, and include nausea, vomiting, excessive thirst, constipation [archbronconeumol.org]

  Possible side effects from chemo include: Fatigue Nausea and vomiting Hair loss Loss of appetite Diarrhea Increased risk of infection Immunotherapy. This treatment uses medicine to boost your immune system's ability to find and destroy cancer. [webmd.com]

• Abdominal Mass

  Clinical manifestation may include epigastric or abdominal pain, weight loss, diabetes, jaundice and palpable abdominal mass. Some patients have no symptoms and the tumor is discovered incidentally. [orpha.net]

  Hepatic adenomas are diagnosed when they cause epigastric or upper quadrant pain or during an imaging study done for unrelated ailments, and less commonly when an abdominal mass is palpated on clinical examination. [intechopen.com]

• Hyperpigmentation

  […] hormone (~25%) Acromegaly : bone enlargement in hand/feet/skull, prominent jaw, cardiomegaly, heat intolerance, weight gain ACTH (~20%) Cushing's disease : central obesity (moon facies, buffalo hump), thin skin with striae, hirsutism Nelson's syndrome : hyperpigmentation [en.wikibooks.org]

  […] carcinoma – Usually proximal bronchi and may be more common on the left side of the tracheobronchial tree Paraneoplastic involvement Endocrinopathies associated with bronchial carcinoids include Cushing syndrome (with increased corticotropin levels), hyperpigmentation [emedicine.medscape.com]

  Approximately 25 percent of patients with MEN1 develop pituitary adenomas.[20][21] Carney complex[edit] Carney complex (CNC), also known as LAMB syndrome[22] and NAME syndrome[22] is an autosomal dominant condition comprising myxomas of the heart and skin, hyperpigmentation [en.wikipedia.org]

  They may also develop hyperpigmentation, which occurs due to the stimulation of melanocytes by POMC. [eyewiki.aao.org]

• Kidney Failure

  A similar but less common condition, called secondary hyperparathyroidism, can occur in people with chronic kidney failure. Approximately 100,000 Americans develop primary hyperparathyroidism each year. [my.clevelandclinic.org]

  Kidney failure is almost always the cause. Secondary hyperparathyroidism is never associated with high blood calcium. HypOparathyroidism is an uncommon complication of parathyroid or thyroid surgery--when all the parathyroids have been removed. [parathyroid.com]

• Renal Insufficiency

  Renal Insufficiency No change in standard management. B. Liver Insufficiency No change in standard management. C. [cancertherapyadvisor.com]

• Incontinence

  Examples of morbidity associated with this condition included spinal cordotomy for intractable pain secondary to lumbar spine disease 11 and sacral resection with excision of the sacral plexus, also leading to paralysis and double incontinence. 30 Independent [jamanetwork.com]

• Urinary Incontinence

  Urinary retention. Irritative symptoms Polyuria, or increased frequency of urination. Nocturia, or the need to urinate frequently during the night. Sudden urge to urinate. Urge urinary incontinence. [urologiaserrateribal.com]

• Urinary Retention

  Urinary retention. Irritative symptoms Polyuria, or increased frequency of urination. Nocturia, or the need to urinate frequently during the night. Sudden urge to urinate. Urge urinary incontinence. [urologiaserrateribal.com]

The workup is dependent on the site of the adenoma and the symptoms that it is causing.

• In case of adenoma of the brain, magnetic resonance imaging is the recommended modality as the adenoma may be seen and this will allow planning for treatment if warranted. 
• For the colon if there is a family history of polyps, whole colon colonoscopy is mandatory otherwise, screening as per local guidelines is recommended.
• Adrenal adenomas most are found incidentally by CT scan and if there are no symptoms suggestive of hormonal secretion, no more laboratory testing is required. 
• For the thyroid gland, ultrasound is the modality of choice, with indications for biopsy being determined by features noted on the ultrasound. Thyroid function tests will also be required to examine the hormone levels.
• Parathyroid adenomas that are symptomatic will require investigations that include calcium levels, urinary calcium levels, renal function tests and parathyroid hormone levels.

The treatment of an adenoma will depend entirely on the location and other symptoms caused by the tumor. Many are asymptomatic and will never require any treatment or follow-up. The symptomatic ones may require surgical removal.

The prognosis varies from the site, but the grade of dysmorphic cells and dysplasia is prognostic, with high grades being more prone to malignant transformation than lower grades. There are some familial adenoma syndromes such as familial adenomatous polyposis which is known to have a high propensity for malignant transformation.

An adenoma occurs due to an abnormal cell proliferation and defective apoptosis. There are believed to be multiple steps in the progression from normal tissue to adenoma, and then ultimately to adenocarcinoma. The processes differs from site to site and involve loss of tumor suppressor genes and activation of oncogenes. Some of these genetic aberrations may be genetically passed down like in familial adenomatous polyposis (FAP), some may be due to external carcinogens.

The epidemiology of adenomas varies from site of origin. The list is not exhaustive:

• Pituitary adenomas represent about 12.5% of all brain tumours [2].
• Population autopsy studies suggest that approximately 30% of people above 40 years of age have colonic adenomas called polyps [3].
• Most adrenal adenomas are found incidentally and are termed incidentaloma and their prevalence ranges from 0.4 to 8.7% from autopsy and CT scan studies [4].
• About 10% of people have an isolated thyroid nodules. Some may require excision of biopsy, and other may secrete hormones [5].
• Parathyroid adenomas may secrete parathyroid hormone and cause primary hyperparathyroidism [6].

The biochemical processes that lead to adenoma formation depend on the location and the underlying cell type. There may be an interplay of genetic and environmental factors with organs exposed to the environment being at higher risk. The tumorgenesis for many of these is just beginning to be elucidated.

Since most are caused by cell proliferation, it is difficult to prevent adenomas. The important aspect it to find the ominous ones early and treat them appropriately to prevent malignant transformation. Families with a strong family history of adenomas like colonic polyps will require screening.

An adenoma is a benign epithelial tumor with glandular origin, glandular characteristics, or both. It may become malignant and can also appear in non-glandular areas. The malignant transformation is rare. It may cause of other complications such as compressive symptoms and autonomous hormone secretion [1]. The adenomas may be at different levels of dysplasia, with the ones with more dysplastic characteristics, having more potential for malignant transformation.

Definition

Adenomas are small swellings that can occur in many locations in the body. Most of them are innocent, but some may cause trouble if they are big enough and compress nearby structures. They have a small potential to become cancers.

Cause

The cause of the growths is unknown, but there is ongoing research into genetics with information growing.

Symptoms

These depend on the site. In the brain there may be headache and problems with eye site. If they are in the colon there may be constipation or diarrhea otherwise most are asymptomatic. Adrenal tumours may secrete hormones that may cause different symptoms such a weight gain and diabetes if corticosteroid are being made, or episodes of palpitations and flushing if adrenaline is being made. Thyroid adenomas may cause a disease called hyperthyroidism which is presents with heat intolerance and weight loss. Parathyroid adenomas may present with symptoms of too much calcium in the body such as aches and stomach pains.

Diagnosis

Diagnosis is dependent on the site, for the brain a CT scan or magnetic resonance imaging may be used. For the colon a colonoscopy. For adrenal adenomas a CT scan and blood tests to check hormone levels may be done. The same for parathyroid adenomas. For thyroid adenomas an ultrasound may be required and a small piece taken for testing.

Treatment

The response of your doctor will depend on the site and the symptoms and the local guidelines. They may requiring occasional screening or removal by surgery if required.

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