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 .
- 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   .
- 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]
[…] 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. Carney complex Carney complex (CNC), also known as LAMB syndrome and NAME syndrome 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]
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 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 .
- Population autopsy studies suggest that approximately 30% of people above 40 years of age have colonic adenomas called polyps .
- 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 .
- About 10% of people have an isolated thyroid nodules. Some may require excision of biopsy, and other may secrete hormones .
- Parathyroid adenomas may secrete parathyroid hormone and cause primary hyperparathyroidism .
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.
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 . The adenomas may be at different levels of dysplasia, with the ones with more dysplastic characteristics, having more potential for malignant transformation.
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.
The cause of the growths is unknown, but there is ongoing research into genetics with information growing.
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 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.
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