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Adenomas



Some risk factors for adenomas are not controllable. However, you can improve your chances of staying healthy by getting regular health screenings. If you have a higher risk of developing an adenoma, ask your healthcare provider how often you should receive screenings.


Adenomas are benign (noncancerous) tumors. However, you should treat adenomas as precancerous because they may turn into cancer if left undetected. The severity of an adenoma can vary greatly, depending on its size and location. If an adenoma is small, you may not need treatment right away. For a larger or problematic adenoma, your healthcare provider may recommend surgery to remove it. Most adenomas that are caught early do not turn into cancer.




adenomas




Adenomas can have several different growth patterns that can be seen under the microscope by the pathologist. There are 2 major growth patterns: tubular and villous. Many adenomas have a mixture of both growth patterns, and are called tubulovillous adenomas. Most adenomas that are small (less than inch) have a tubular growth pattern. Larger adenomas may have a villous growth pattern. Larger adenomas more often have cancers developing in them. Adenomas with a villous growth pattern are also more likely to have cancers develop in them.


An adenoma is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organs, including the adrenal glands, pituitary gland, thyroid, prostate, and others. Some adenomas grow from epithelial tissue in nonglandular areas but express glandular tissue structure (as can happen in familial polyposis coli). Although adenomas are benign, they should be treated as pre-cancerous. Over time adenomas may transform to become malignant, at which point they are called adenocarcinomas. Most adenomas do not transform. However, even though benign, they have the potential to cause serious health complications by compressing other structures (mass effect) and by producing large amounts of hormones in an unregulated, non-feedback-dependent manner (causing paraneoplastic syndromes). Some adenomas are too small to be seen macroscopically but can still cause clinical symptoms.[citation needed]


Ashkenazi Jews have a 6% higher risk rate of getting adenomas, and then colon cancer, than do the general population, so it is important that they have regular actual colonoscopies, and specifically none of the less invasive diagnostic methods.[1]


Adrenal adenomas are common, and are often found on the abdomen, usually not as the focus of investigation; they are usually incidental findings. About one in 10,000 is malignant. Thus, a biopsy is rarely called for, especially if the lesion is homogeneous and smaller than 3 centimeters. Follow-up images in three to six months can confirm the stability of the growth.


Pituitary adenomas are seen in 10% of neurological patients. A lot of them remain undiagnosed. Treatment is usually surgical, to which patients generally respond well. The most common subtype, prolactinoma, is seen more often in women, and is frequently diagnosed during pregnancy as the hormone progesterone increases its growth. Medical therapy with cabergoline or bromocriptine generally suppresses prolactinomas; progesterone antagonist therapy has not proven to be successful.


A physician's response to detecting an adenoma in a patient will vary according to the type and location of the adenoma among other factors.[citation needed] Different adenomas will grow at different rates, but typically physicians can anticipate the rates of growth because some types of common adenomas progress similarly in most patients.[citation needed] Two common responses are removing the adenoma with surgery and then monitoring the patient according to established guidelines.[citation needed]


Endocrine tumors such as aldosterone-producing adrenal adenomas (APAs), a cause of severe hypertension, feature constitutive hormone production and unrestrained cell proliferation; the mechanisms linking these events are unknown. We identify two recurrent somatic mutations in and near the selectivity filter of the potassium (K(+)) channel KCNJ5 that are present in 8 of 22 human APAs studied. Both produce increased sodium (Na(+)) conductance and cell depolarization, which in adrenal glomerulosa cells produces calcium (Ca(2+)) entry, the signal for aldosterone production and cell proliferation. Similarly, we identify an inherited KCNJ5 mutation that produces increased Na(+) conductance in a Mendelian form of severe aldosteronism and massive bilateral adrenal hyperplasia. These findings explain pathogenesis in a subset of patients with severe hypertension and implicate loss of K(+) channel selectivity in constitutive cell proliferation and hormone production.


Methods: Three demographically and geographically distinct districts of the province of Liège were delineated precisely using postal codes. Medical practitioners in these districts were recruited, and patients with pituitary adenomas under their care were identified. Diagnoses were confirmed after retrieval of clinical, hormonal, radiological, and pathological data; full demographic and therapeutic follow-up data were collected in all cases.


Results: Sixty-eight patients with clinically relevant pituitary adenomas were identified in a population of 71,972 individuals; the mean (+/- sd) prevalence was 94 +/- 19.3 cases per 100,000 population (95% confidence interval, 72.2 to 115.8). The group was 67.6% female and had a mean age at diagnosis of 40.3 yr; 42.6% had macroadenomas and 55.9% underwent surgery. Prolactinomas comprised 66% of the group, with the rest having nonsecreting tumors (14.7%), somatotropinomas (13.2%), or Cushing's disease (5.9%); 20.6% had hypopituitarism.


Conclusion: The prevalence of pituitary adenomas in the study population (one case in 1064 individuals) was more than 3.5-5 times that previously reported. This increased prevalence may have important implications when prioritizing funding for research and treatment of pituitary adenomas.


The most commonly occurring pituitary adenomas in this disorder are growth hormone-secreting adenomas (somatotropinoma), followed by prolactin-secreting adenomas (prolactinoma), growth hormone and prolactin co-secreting adenomas (somatomammotropinoma), and nonfunctioning pituitary adenomas (NFPA). Rarely TSH-secreting adenomas (thyrotropinomas) are observed. Clinical findings result from excess hormone secretion, lack of hormone secretion, and/or mass effects (e.g., headaches, visual field loss). Within the same family, pituitary adenomas can be of the same or different type. Age of onset in AIP-FIPA is usually in the second or third decade.


Treatment of manifestations: Pituitary adenomas identified in those with AIP-FIPA are generally treated in the same manner as pituitary adenomas of unknown cause: they can be treated by medical therapy (somatostatin analogs, growth hormone receptor antagonists, and dopamine agonists), surgery, and/or radiotherapy. Although surgery is usually performed in persons with AIP-FIPA, it often does not fully control the tumor; thus, medical therapy and radiotherapy following surgery may be required to control hormone output and tumor growth. AIP-FIPA adenomas often do not respond well to first-generation somatostatin analog, while data suggest that they may respond better to second-generation multi-ligand agonists. Prolactinomas are treated with dopamine agonist therapy or surgery and can be aggressive and difficult to treat. NFPA is treated with surgery and if necessary radiotherapy.


Evaluation of relatives at risk: Family members at risk for AIP-FIPA warrant molecular genetic testing for the family-specific pathogenic variant to identify those who harbor the variant and thus require surveillance for pituitary adenomas.


NFPAs are usually diagnosed due to the local effects of the tumor, such as bitemporal hemianopia or hypogonadism. It is unclear why these silent adenomas do not release hormones at a clinically recognizable level; however, there is likely to be a continuum between fully functional and completely silent adenomas [Drummond et al 2019]. Distinguishing NFPA from prolactinomas can occasionally be difficult due to the stalk effect (pituitary stalk compression resulting in increased prolactin levels in the absence of a prolactin-secreting adenoma).


In AIP-FIPA, NFPAs that have been resected are often (but not always) silent somatotropinoma or lactotroph adenomas [Igreja et al 2010, Villa et al 2011]. In families with AIP-FIPA, NFPAs are identified at a younger age than NFPAs in persons without a germline pathogenic variant [Daly et al 2010]. Screening of clinically unaffected AIP heterozygotes can identify small nonfunctioning pituitary lesions, equivalent to incidentalomas in the general population [Caimari et al 2018].


Mass effects. Large pituitary adenomas can be associated with deficiencies of other pituitary hormones that result in subfertility, hypothyroidism, hypoadrenalism, low levels of growth hormone, and panhypopituitarism.


Macroadenomas (>10 mm in diameter) may also press on the optic chiasm and optic tracts, causing bitemporal hemianopia. The tumor may invade the adjacent cavernous sinus. Headache can be present in any type of adenoma but is especially common in acromegaly; the mechanism for the increased frequency is unknown.


Studies on large families with AIP pathogenic variants show a clinical penetrance of pituitary adenomas of approximately 23% (range 15%-30%) [Vierimaa et al 2006, Naves et al 2007, Williams et al 2014, Hernández-Ramírez et al 2015]. Although some families with AIP-FIPA can show high penetrance, the higher levels of penetrance initially reported in some families is probably ascertainment bias due to insufficient information on all at-risk family members (e.g., lack of medical records, information on pituitary hormone testing, and/or imaging studies) [Daly et al 2007, Leontiou et al 2008]. 2ff7e9595c


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