Incidentaloma overview: Difference between revisions
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==Historical Perspective== | ==Historical Perspective== | ||
In 1979, Korobkin et al. was the first to discover incidentaloma. In 1989, a large study at the Mayo Clinic found a 3.4% [[prevalence]] of [[adrenal incidentaloma]]. | |||
==Classification== | ==Classification== | ||
==Pathophysiology== | ==Pathophysiology== | ||
The pathophysiology of adrenal incidentaloma depends on nature of the [[mass]] and its function. Incidentalomas are [[Adrenal gland|adrena]]<nowiki/>l [[Tumor|tumors]] that often discovered as an incidental finding. [[Malignancy]] is an uncommon cause of [[Adrenal gland|adrenal]] incidentaloma in patients without a known diagnosis of cancer. It may secrete cortisol. [[Cushing's syndrome]] is linked to [[hypercortisolism]] which can develop by excess [[ACTH]] secretion or excess [[cortisol]] secretion by [[adrenal glands]]. It may secrete catecholanines and in this case it is considered pheochromocytoma. [[Pheochromocytoma]] arises from [[chromaffin cells]] of the [[adrenal medulla]] and [[Sympathetic ganglion|sympathetic ganglia]]. [[Malignant]] and [[benign]] [[Pheochromocytoma|pheochromocytomas]] share the same [[biochemical]] and [[histological]] features, the only difference is to have a distant spread or be locally invasive. It may be sporadic, but some occur as a component of hereditary cancer syndromes such as [[Li-Fraumeni syndrome]], [[Beckwith-Wiedemann syndrome]], and [[Multiple endocrine neoplasia type 1]]. Genetic base of sporadic incidentaloma is mutations in ''[[TP53 (gene)|TP53]]'' [[gene]], located on [[chromosome]] 17p13. A role for the ''[[TP53 (gene)|TP53]]'' [[tumor suppressor gene]] in sporadic adrenocortical carcinoma. On gross pathology, adrenocortical adenoma is a well circumscribed, yellow tumour in the [[adrenal cortex]], which is usually 2–5 cm in diameter. The color of tumor, as with [[adrenal cortex]] as a whole, is due to the stored lipid (mainly [[Cholesterol|cholesterol)]], from which the [[Adrenal cortex|cortical]] [[hormones]] are synthesized. | |||
==Causes== | ==Causes== | ||
Common causes of incidentaloma include [[adenoma]], [[carcinoma]], [[pheochromocytoma]][[Congenital adrenal hyperplasia|, congenital adrenal hyperplasia]], massive macronodular adrenal disease, and nodular variant of [[Cushing’s disease]]. Less Common Causes include [[Myelolipoma|myelolipoma,]] [[neuroblastoma]], [[ganglioneuroma]], [[hemangioma]]. | |||
==Differentiating | ==Differentiating adrenal incidentaloma from Other Diseases== | ||
[[Adrenal gland|Adrenal]] incidentaloma must be differentiated from other diseases that cause adrenal masses such as adrenal [[adenoma]], [[adrenocortical carcinoma]], [[Cushing's syndrome]], [[pheochromocytoma]], and [[metastasis]]. | |||
==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
[[Prevalence]] of clinically inapparent adrenal masses is around 2% in [[Autopsy|autopsy studies]]. Radiological studies report a frequency of around 3%. The prevalence of adrenal incidentalomas increases with age. The prevalence of adrenal incidentaloma is higher in older patients 10%. There is no racial or gender predilection to incidentaloma. | |||
==Risk Factors== | ==Risk Factors== | ||
==Screening== | ==Screening== | ||
According to the European Society of Endocrinology Clinical Practice Guideline, screening for adrenal incidentaloma includes: family screening for patients with bilateral macronodular [[hyperplasia]], patients with asymptomatic [[vertebral fractures]], patients with possible autonomous [[cortisol]] secretion, patients with a hereditary syndrome leading to [[Adrenal tumor|adrenal tumors]]. Screening test include 24-hour urine [[Metanephrine|fractionated metanephrines]] for [[pheochromocytoma]], 24-hour urinary free [[cortisol]] for patients with symptoms of [[Cushing's syndrome]], and [[Aldosterone|Plasma aldosterone concentration]], [[plasma renin activity]] for patients with [[Primary hyperaldosteronism|Primary aldosteronism]]. | |||
==Natural History, Complications, and Prognosis== | ==Natural History, Complications, and Prognosis== | ||
If left untreated, patients with adrenal incidentaloma may progress to develop [[dyslipidemia]], [[osteoporosis]], [[hyperglycemia]], [[malignant hypertension]], [[intracranial hemorrhage]], [[acute coronary syndrome]], [[aortic dissection]], [[malignant]] transformation, and metastasis. Prognosis is usually good in [[benign]] [[Adrenal gland|adrenal]] incidentalomas, death is not directly related to the [[Adrenal mass causes|adrenal mass]], but to [[cardiovascular]] accidents, [[malignancy]], and chronic disorders, as observed in the general population. [[Adrenocortical carcinoma]] (ACC) carries a poor prognosis and is unlike most tumors of the [[Adrenal cortex|adrenal cortex,]] which are [[benign]] ([[adenomas]]) and only occasionally cause Cushing's syndrome. | |||
==Diagnosis== | ==Diagnosis== | ||
===Diagnostic Criteria=== | ===Diagnostic Criteria=== | ||
===History and Symptoms=== | ===History and Symptoms=== | ||
Subclinical [[Cushing's syndrome]] which includes [[diabetes]], and a high incidence of [[vertebral fractures]], [[dyslipidemia]], [[impaired glucose tolerance]] or [[Diabetes mellitus type 2|type 2 diabetes mellitus]], and evidence of [[atherosclerosis]]. [[Pheochromocytoma]]: Paroxysmal attacks of [[Hypertension|hypertension,]] [[palpitation]], [[diaphoresis]], [[headache]], [[pallor]], and [[Tremor|tremor.]] Primary [[hyperaldosteronism]] patients show [[hypertension]] and [[hypokalemia]]. Approximately 60 percent of [[Adrenocortical carcinoma|adrenocortical carcinomas]] (ACCs) are sufficiently secretory to present clinical [[syndrome]] of [[hormone]] excess. Family history of [[Li-Fraumeni syndrome]], [[Beckwith-Wiedemann syndrome]], and [[Multiple endocrine neoplasia type 1 (patient information)|multiple endocrine neoplasia type 1]] ([[MEN1]]). | |||
===Physical Examination=== | ===Physical Examination=== | ||
Common physical examination findings of include patients may appear quite well if the [[disease]] is [[asymptomatic]]. Patients may appear tired, weak, [[diaphoretic]] and [[anxious]]. [[Tachypnea]] if [[malignant]] secondaries are found in the [[lung]] with rapid strong equal [[pulse]] and high [[blood pressure]]. [[Jaundice]], [[Hyperpigmentation|hyperpigmentation,]] [[telangiectasia]], thinning of the skin and easy bruising may be found. [[Abdominal distention]] in patients with [[primary hyperparathyroidism]] associated [[constipation]]. A palpable [[abdominal mass]] in the lower [[abdominal]] quadrant. [[Hyporeflexia]] due to low [[potassium]] level in [[Hyperaldosteronism|aldosternonma]], [[proximal]] [[muscle weakness]] bilaterally, and bilateral [[tremors]] may be found also. | |||
===Laboratory Findings=== | ===Laboratory Findings.=== | ||
Laboratory findings consistent with the diagnosis of incidentaloma include an abnormal 1 mg overnight [[dexamethasone]] for subclinical [[Cushing's syndrome]] that should be confirmed with 24-hour urinary free [[cortisol]], serum [[Adrenocorticotropic hormone|ACTH]] concentration, and [[dehydroepiandrosterone sulfate]] ([[DHEAS]]). In patients with [[Adrenal gland|adrenal]] masses that have a probability for [[pheochromocytoma]], routine measurement of 24-hour urinary fractionated [[Metanephrine|metanephrines]] and [[catecholamines]] should be done. All patients with [[hypertension]] and an [[Adrenal gland|adrenal]] incidentaloma should be evaluated by measurements of plasma [[aldosterone]] concentration and plasma [[renin]] activity. | |||
===Electrocardiogram=== | ===Electrocardiogram and UltraSound=== | ||
===X-ray=== | ===X-ray=== | ||
There are no x-ray findings associated with adrenal incidentaloma. | |||
===CT scan=== | ===CT scan=== | ||
Abdominal CT scan may be helpful in the diagnosis of [disease name]. Differentiation between [[benign]] and [[malignant]] incidentaloma is important. [[Malignancy]] is suggested on [[Computed tomography|CT]] by a large diameter more than 6 cms, irregular border, inhomogeneity, a “washout” of contrast after 15 min of less than 40%, and [[Calcification|calcifications]]. [[Contrast medium|Contrast]]-enhanced washout [[Computed tomography|CT]] utilizes the unique perfusion pattern of [[adenomas]]. [[Adenomas]] take up intravenous [[Computed tomography|CT]] contrast rapidly, but also have a rapid loss of [[Contrast medium|contrast]] – a phenomenon termed ‘[[contrast]] enhancement washout’. It is assumed that [[malignant]] [[Adrenal gland|adrenal]] lesions usually enhance rapidly but demonstrate a slower washout of [[Contrast medium|contrast]] medium. | |||
===MRI=== | ===MRI=== | ||
[[Adrenal gland|Adrenal]] [[Magnetic resonance imaging|MRI]] may be helpful in the diagnosis of incidentaloma. Findings on [[Magnetic resonance imaging|MRI]] suggestive of incidentaloma include mild enhancement and a rapid washout of [[Contrast medium|contrast,]] while [[malignant]]<nowiki/>lesions show rapid and marked enhancement and a slower washout pattern. [[Magnetic resonance imaging|MRI]] has advantages in certain clinical situations. The advantages of [[Magnetic resonance imaging|MRI]] over [[Computed tomography|CT]] are its lack of radiation exposure, lack of [[iodine]]-based contrast media and its superior tissue contrast resolution. | |||
===Other Imaging Findings=== | ===Other Imaging Findings=== | ||
Findings on a [[Positron emission tomography|Positron Emission Tomography]] ([[Positron emission tomography|PET-CT]]) scan suggestive of/diagnostic of incidentaloma. [[Cancer]] cells have an increased requirement for [[glucose]] and take up more [[glucose]] and deoxyglucose than normal cells. standard uptake value (SUV) values have been utilized to differentiate between [[benign]] and [[malignant]] adrenal lesions. It may be helpful in the diagnosis of incidentaloma in selected patients; those with a history of [[malignancy]] or those in which [[Computed tomography|CT]] [[densitometry]] or washout analysis is inconclusive or suspicious for [[malignancy]]<nowiki/>because of their high sensitivity for detecting [[Malignancy|malignancy.]] | |||
===Other Diagnostic Studies=== | ===Other Diagnostic Studies=== | ||
[[Needle aspiration biopsy|Fine-needle aspiration biopsy]] may be helpful in the diagnosis of incidentaloma. It can distinguish between an [[Adrenal gland|adrena]]<nowiki/>l tumor and a [[Metastasis|metastatic]] tumor. In a patient with a known primary [[malignancy]], performing a diagnostic [[Computed tomography|CT]]-guided [[Needle aspiration biopsy|FNA]] biopsy may be indicated. The [[Needle aspiration biopsy|FNA]] biopsy of a [[pheochromocytoma]] may result in [[hemorrhage]] and [[hypertensive crisis]]. So, excluding [[pheochromocytoma]] with biochemical testing is necessary before any procedure. | |||
==Treatment== | ==Treatment== | ||
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===Surgery=== | ===Surgery=== | ||
Surgery is the mainstay of treatment for [disease or malignancy]. [[Adrenalectomy]] for patients with [[Hyperaldosteronism|aldosteronomas]], [[pheochromocytoma]], [[Cortisol-secreting tumor|cortisol-secreting tumors]], and [[Adrenal gland|adrenal]]<nowiki/>incidentalomas is safe and effective. A reasonable strategy may be to consider [[adrenalectomy]] for younger patients and those with new onset or a worsening of underlying comorbidities such as [[diabetes mellitus]], [[hypertension]], [[obesity]], or [[osteoporosis]]. All patients with documented [[pheochromocytoma]] and [[Adrenocortical carcinoma|adrenocortical cancer]] should undergo prompt surgical intervention. Risk factors for complications during surgery include high [[plasma]] [[norepinephrine]] concentration and larger [[tumor]] size. | |||
===Primary Prevention=== | ===Primary Prevention=== | ||
===Secondary Prevention=== | ===Secondary Prevention=== | ||
Effective measures for the [[secondary prevention]] of [[adrenal incidentaloma]] include annual [[biochemical]] follow-up for up to 5 yr, no routine follow-up of [[Adrenal incidentaloma|adrenal incidentalomas]] with a non-[[Contrast medium|contrast attenuation]] value no greater than 10 HU. Patients with [[Adrenal mass causes|adrenal masses]] less than 4 cm in size and a [[Contrast medium|non-contrast]] attenuation value more than 10 HU should have a repeat [[Computed tomography|CT]]<nowiki/>study in 3–6 months and then yearly for 2 yr. | |||
==References== | ==References== | ||
Revision as of 21:33, 5 September 2017
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Historical Perspective
In 1979, Korobkin et al. was the first to discover incidentaloma. In 1989, a large study at the Mayo Clinic found a 3.4% prevalence of adrenal incidentaloma.
Classification
Pathophysiology
The pathophysiology of adrenal incidentaloma depends on nature of the mass and its function. Incidentalomas are adrenal tumors that often discovered as an incidental finding. Malignancy is an uncommon cause of adrenal incidentaloma in patients without a known diagnosis of cancer. It may secrete cortisol. Cushing's syndrome is linked to hypercortisolism which can develop by excess ACTH secretion or excess cortisol secretion by adrenal glands. It may secrete catecholanines and in this case it is considered pheochromocytoma. Pheochromocytoma arises from chromaffin cells of the adrenal medulla and sympathetic ganglia. Malignant and benign pheochromocytomas share the same biochemical and histological features, the only difference is to have a distant spread or be locally invasive. It may be sporadic, but some occur as a component of hereditary cancer syndromes such as Li-Fraumeni syndrome, Beckwith-Wiedemann syndrome, and Multiple endocrine neoplasia type 1. Genetic base of sporadic incidentaloma is mutations in TP53 gene, located on chromosome 17p13. A role for the TP53 tumor suppressor gene in sporadic adrenocortical carcinoma. On gross pathology, adrenocortical adenoma is a well circumscribed, yellow tumour in the adrenal cortex, which is usually 2–5 cm in diameter. The color of tumor, as with adrenal cortex as a whole, is due to the stored lipid (mainly cholesterol), from which the cortical hormones are synthesized.
Causes
Common causes of incidentaloma include adenoma, carcinoma, pheochromocytoma, congenital adrenal hyperplasia, massive macronodular adrenal disease, and nodular variant of Cushing’s disease. Less Common Causes include myelolipoma, neuroblastoma, ganglioneuroma, hemangioma.
Differentiating adrenal incidentaloma from Other Diseases
Adrenal incidentaloma must be differentiated from other diseases that cause adrenal masses such as adrenal adenoma, adrenocortical carcinoma, Cushing's syndrome, pheochromocytoma, and metastasis.
Epidemiology and Demographics
Prevalence of clinically inapparent adrenal masses is around 2% in autopsy studies. Radiological studies report a frequency of around 3%. The prevalence of adrenal incidentalomas increases with age. The prevalence of adrenal incidentaloma is higher in older patients 10%. There is no racial or gender predilection to incidentaloma.
Risk Factors
Screening
According to the European Society of Endocrinology Clinical Practice Guideline, screening for adrenal incidentaloma includes: family screening for patients with bilateral macronodular hyperplasia, patients with asymptomatic vertebral fractures, patients with possible autonomous cortisol secretion, patients with a hereditary syndrome leading to adrenal tumors. Screening test include 24-hour urine fractionated metanephrines for pheochromocytoma, 24-hour urinary free cortisol for patients with symptoms of Cushing's syndrome, and Plasma aldosterone concentration, plasma renin activity for patients with Primary aldosteronism.
Natural History, Complications, and Prognosis
If left untreated, patients with adrenal incidentaloma may progress to develop dyslipidemia, osteoporosis, hyperglycemia, malignant hypertension, intracranial hemorrhage, acute coronary syndrome, aortic dissection, malignant transformation, and metastasis. Prognosis is usually good in benign adrenal incidentalomas, death is not directly related to the adrenal mass, but to cardiovascular accidents, malignancy, and chronic disorders, as observed in the general population. Adrenocortical carcinoma (ACC) carries a poor prognosis and is unlike most tumors of the adrenal cortex, which are benign (adenomas) and only occasionally cause Cushing's syndrome.
Diagnosis
Diagnostic Criteria
History and Symptoms
Subclinical Cushing's syndrome which includes diabetes, and a high incidence of vertebral fractures, dyslipidemia, impaired glucose tolerance or type 2 diabetes mellitus, and evidence of atherosclerosis. Pheochromocytoma: Paroxysmal attacks of hypertension, palpitation, diaphoresis, headache, pallor, and tremor. Primary hyperaldosteronism patients show hypertension and hypokalemia. Approximately 60 percent of adrenocortical carcinomas (ACCs) are sufficiently secretory to present clinical syndrome of hormone excess. Family history of Li-Fraumeni syndrome, Beckwith-Wiedemann syndrome, and multiple endocrine neoplasia type 1 (MEN1).
Physical Examination
Common physical examination findings of include patients may appear quite well if the disease is asymptomatic. Patients may appear tired, weak, diaphoretic and anxious. Tachypnea if malignant secondaries are found in the lung with rapid strong equal pulse and high blood pressure. Jaundice, hyperpigmentation, telangiectasia, thinning of the skin and easy bruising may be found. Abdominal distention in patients with primary hyperparathyroidism associated constipation. A palpable abdominal mass in the lower abdominal quadrant. Hyporeflexia due to low potassium level in aldosternonma, proximal muscle weakness bilaterally, and bilateral tremors may be found also.
Laboratory Findings.
Laboratory findings consistent with the diagnosis of incidentaloma include an abnormal 1 mg overnight dexamethasone for subclinical Cushing's syndrome that should be confirmed with 24-hour urinary free cortisol, serum ACTH concentration, and dehydroepiandrosterone sulfate (DHEAS). In patients with adrenal masses that have a probability for pheochromocytoma, routine measurement of 24-hour urinary fractionated metanephrines and catecholamines should be done. All patients with hypertension and an adrenal incidentaloma should be evaluated by measurements of plasma aldosterone concentration and plasma renin activity.
Electrocardiogram and UltraSound
X-ray
There are no x-ray findings associated with adrenal incidentaloma.
CT scan
Abdominal CT scan may be helpful in the diagnosis of [disease name]. Differentiation between benign and malignant incidentaloma is important. Malignancy is suggested on CT by a large diameter more than 6 cms, irregular border, inhomogeneity, a “washout” of contrast after 15 min of less than 40%, and calcifications. Contrast-enhanced washout CT utilizes the unique perfusion pattern of adenomas. Adenomas take up intravenous CT contrast rapidly, but also have a rapid loss of contrast – a phenomenon termed ‘contrast enhancement washout’. It is assumed that malignant adrenal lesions usually enhance rapidly but demonstrate a slower washout of contrast medium.
MRI
Adrenal MRI may be helpful in the diagnosis of incidentaloma. Findings on MRI suggestive of incidentaloma include mild enhancement and a rapid washout of contrast, while malignantlesions show rapid and marked enhancement and a slower washout pattern. MRI has advantages in certain clinical situations. The advantages of MRI over CT are its lack of radiation exposure, lack of iodine-based contrast media and its superior tissue contrast resolution.
Other Imaging Findings
Findings on a Positron Emission Tomography (PET-CT) scan suggestive of/diagnostic of incidentaloma. Cancer cells have an increased requirement for glucose and take up more glucose and deoxyglucose than normal cells. standard uptake value (SUV) values have been utilized to differentiate between benign and malignant adrenal lesions. It may be helpful in the diagnosis of incidentaloma in selected patients; those with a history of malignancy or those in which CT densitometry or washout analysis is inconclusive or suspicious for malignancybecause of their high sensitivity for detecting malignancy.
Other Diagnostic Studies
Fine-needle aspiration biopsy may be helpful in the diagnosis of incidentaloma. It can distinguish between an adrenal tumor and a metastatic tumor. In a patient with a known primary malignancy, performing a diagnostic CT-guided FNA biopsy may be indicated. The FNA biopsy of a pheochromocytoma may result in hemorrhage and hypertensive crisis. So, excluding pheochromocytoma with biochemical testing is necessary before any procedure.
Treatment
Medical Therapy
Surgery
Surgery is the mainstay of treatment for [disease or malignancy]. Adrenalectomy for patients with aldosteronomas, pheochromocytoma, cortisol-secreting tumors, and adrenalincidentalomas is safe and effective. A reasonable strategy may be to consider adrenalectomy for younger patients and those with new onset or a worsening of underlying comorbidities such as diabetes mellitus, hypertension, obesity, or osteoporosis. All patients with documented pheochromocytoma and adrenocortical cancer should undergo prompt surgical intervention. Risk factors for complications during surgery include high plasma norepinephrine concentration and larger tumor size.
Primary Prevention
Secondary Prevention
Effective measures for the secondary prevention of adrenal incidentaloma include annual biochemical follow-up for up to 5 yr, no routine follow-up of adrenal incidentalomas with a non-contrast attenuation value no greater than 10 HU. Patients with adrenal masses less than 4 cm in size and a non-contrast attenuation value more than 10 HU should have a repeat CTstudy in 3–6 months and then yearly for 2 yr.