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In medicine, an 'incidentaloma' is a tumor (''-oma'') found by coincidence (''incidental'') without clinical symptoms and suspicion. It is a common problem: up to 7% of all patients over 60 may harbor a benign growth, often of the adrenal gland, which is detected when diagnostic imaging is used for the analysis of unrelated symptoms. With the increase of "whole-body CT scanning" as part of health screening programs, the chance of finding incidentalomas is expected to increase. 37% of patients receiving whole-body CT scan may have abnormal findings that need further evaluation.[1]
When faced with an unexpected finding on diagnostic imaging, the clinician faces the challenge to prove that the lesion is indeed harmless. Often, some other tests are required to determine the exact nature of an incidentaloma.
In adrenal gland tumors, a dexamethasone suppression test is often used to detect cortisol excess, and metanephrines or catecholamines for excess of these hormones. Tumors under 3 cm are generally considered benign and are only treated if there are grounds for a diagnosis of Cushing's syndrome or pheochromocytoma.[2]
Hormonal evaluation includes[3]:
★ 1-mg overnight dexamethasone suppression test
★ 24-hour urinary specimen for measurement of fractionated metanephrines and catecholamines
★ plasma aldosterone concentration and plasma renin activity ''if hypertension is present''
On CT scan, benign adenomas typically are low radiographic density (due to fat content) and rapid washout of contrast medium (50% or more of the contrast medium washes out at 10 minutes). If the hormonal evaluation is negative and imaging suggests benign, followup should be considered with imaging at 6, 12, and 24 months and repeat hormonal evaluation yearly for 4 years
Most renal cell cancers are now found incidentally.[4] Tumors less than 3 cm in diameter less frequently have aggressive histology.[5]
Autopsy series have suggested that pituitary incidentalomas may be quite common. It has been estimated that perhaps 10% of the adult population may harbor such endocrinologically inert lesions.[6] When encountering such a lesion, long term surveillance has been recommended.[7] Also baseline pituitary hormonal function needs to be checked, including measurements of serum levels of TSH, prolactin, IGF-I (as a test of growth hormone activity), adrenal function (i.e. 24 hours urine corticol,dexamethasone suppression test). teststerone in men and estradial in amenorrheic women.
Incidental thyroid masses may be found in 9% of patients undergoing bilateral carotid duplex ultrasonography. [8]
Some experts[9] recommend that nodules > 1 cm (unless the TSH is suppressed) or those with ultrasonographic features of malignancy should be biopsied by fine needle aspiration. Computed tomography is inferior to ultrasound for evaluating thyroid nodules.[10] Ultrasonographic markers of malignancy are[11]:
★ solid hypoechoic appearance
★ irregular or blurred margins
★ intranodular vascular pattern
★ microcalcifications
★ Irregular margins
★ intranodular vascular spots
★ microcalcifications
Incidental parathyroid masses may be found in 0.1% of patients undergoing bilateral carotid duplex ultrasonography. [8]
Other organs that can harbor incidentalomas include the liver (often a hemangioma).
The concept of the incidentaloma has been criticized, as such lesions do not have much in common other than the history of an incidental identification and the assumption that they are clinically inert. It has been proposed just to say that such lesions have been "incidentally found."[13] The underlying pathology shows no unifying histological concept.
1. Whole-body CT screening: spectrum of findings and recommendations in 1192 patients, Furtado CD, Aguirre DA, Sirlin CB, ''et al'', , , Radiology, 2005
2. Management of the clinically inapparent adrenal mass ("incidentaloma"), Grumbach MM, Biller BM, Braunstein GD, ''et al'', , , Ann. Intern. Med., 2003
3. Clinical practice. The incidentally discovered adrenal mass, Young WF, , , N. Engl. J. Med., 2007
4. Management of small renal tumors: an overview, Reddan DN, Raj GV, Polascik TJ, , , Am. J. Med., 2001
5. Are small renal tumors harmless? Analysis of histopathological features according to tumors 4 cm or less in diameter, Remzi M, Ozsoy M, Klingler HC, ''et al'', , , J. Urol., 2006
6. Pituitary magnetic resonance imaging in normal human volunteers: occult adenomas in the general population, Hall WA, Luciano MG, Doppman JL, Patronas NJ, Oldfield EH, , , Ann. Intern. Med., 1994
7. Pituitary incidentalomas, Molitch ME, , , Endocrinol. Metab. Clin. North Am., 1997
8. The significance of incidental thyroid abnormalities identified during carotid duplex ultrasonography, Steele SR, Martin MJ, Mullenix PS, Azarow KS, Andersen CA, , , Archives of surgery (Chicago, Ill. : 1960), 2005
9. Continuing controversies in the management of thyroid nodules, Castro MR, Gharib H, , , Ann. Intern. Med., 2005
10. Significance of incidental thyroid lesions detected on CT: correlation among CT, sonography, and pathology, Shetty SK, Maher MM, Hahn PF, Halpern EF, Aquino SL, , , AJR. American journal of roentgenology, 2006
11. Risk of malignancy in nonpalpable thyroid nodules: predictive value of ultrasound and color-Doppler features, Papini E, Guglielmi R, Bianchini A, ''et al'', , , J. Clin. Endocrinol. Metab., 2002
12. The significance of incidental thyroid abnormalities identified during carotid duplex ultrasonography, Steele SR, Martin MJ, Mullenix PS, Azarow KS, Andersen CA, , , Archives of surgery (Chicago, Ill. : 1960), 2005
13. Benign anatomical mistakes: incidentaloma, Mirilas P, Skandalakis JE, , , The American surgeon, 2002
When faced with an unexpected finding on diagnostic imaging, the clinician faces the challenge to prove that the lesion is indeed harmless. Often, some other tests are required to determine the exact nature of an incidentaloma.
| Contents |
| Adrenal incidentaloma |
| Renal incidentaloma |
| Pituitary incidentaloma |
| Thyroid incidentaloma |
| Parathyroid incidentaloma |
| Others |
| Scientific criticism |
| References |
Adrenal incidentaloma
In adrenal gland tumors, a dexamethasone suppression test is often used to detect cortisol excess, and metanephrines or catecholamines for excess of these hormones. Tumors under 3 cm are generally considered benign and are only treated if there are grounds for a diagnosis of Cushing's syndrome or pheochromocytoma.[2]
Hormonal evaluation includes[3]:
★ 1-mg overnight dexamethasone suppression test
★ 24-hour urinary specimen for measurement of fractionated metanephrines and catecholamines
★ plasma aldosterone concentration and plasma renin activity ''if hypertension is present''
On CT scan, benign adenomas typically are low radiographic density (due to fat content) and rapid washout of contrast medium (50% or more of the contrast medium washes out at 10 minutes). If the hormonal evaluation is negative and imaging suggests benign, followup should be considered with imaging at 6, 12, and 24 months and repeat hormonal evaluation yearly for 4 years
Renal incidentaloma
Most renal cell cancers are now found incidentally.[4] Tumors less than 3 cm in diameter less frequently have aggressive histology.[5]
Pituitary incidentaloma
Autopsy series have suggested that pituitary incidentalomas may be quite common. It has been estimated that perhaps 10% of the adult population may harbor such endocrinologically inert lesions.[6] When encountering such a lesion, long term surveillance has been recommended.[7] Also baseline pituitary hormonal function needs to be checked, including measurements of serum levels of TSH, prolactin, IGF-I (as a test of growth hormone activity), adrenal function (i.e. 24 hours urine corticol,dexamethasone suppression test). teststerone in men and estradial in amenorrheic women.
Thyroid incidentaloma
Incidental thyroid masses may be found in 9% of patients undergoing bilateral carotid duplex ultrasonography. [8]
Some experts[9] recommend that nodules > 1 cm (unless the TSH is suppressed) or those with ultrasonographic features of malignancy should be biopsied by fine needle aspiration. Computed tomography is inferior to ultrasound for evaluating thyroid nodules.[10] Ultrasonographic markers of malignancy are[11]:
★ solid hypoechoic appearance
★ irregular or blurred margins
★ intranodular vascular pattern
★ microcalcifications
★ Irregular margins
★ intranodular vascular spots
★ microcalcifications
Parathyroid incidentaloma
Incidental parathyroid masses may be found in 0.1% of patients undergoing bilateral carotid duplex ultrasonography. [8]
Others
Other organs that can harbor incidentalomas include the liver (often a hemangioma).
Scientific criticism
The concept of the incidentaloma has been criticized, as such lesions do not have much in common other than the history of an incidental identification and the assumption that they are clinically inert. It has been proposed just to say that such lesions have been "incidentally found."[13] The underlying pathology shows no unifying histological concept.
References
1. Whole-body CT screening: spectrum of findings and recommendations in 1192 patients, Furtado CD, Aguirre DA, Sirlin CB, ''et al'', , , Radiology, 2005
2. Management of the clinically inapparent adrenal mass ("incidentaloma"), Grumbach MM, Biller BM, Braunstein GD, ''et al'', , , Ann. Intern. Med., 2003
3. Clinical practice. The incidentally discovered adrenal mass, Young WF, , , N. Engl. J. Med., 2007
4. Management of small renal tumors: an overview, Reddan DN, Raj GV, Polascik TJ, , , Am. J. Med., 2001
5. Are small renal tumors harmless? Analysis of histopathological features according to tumors 4 cm or less in diameter, Remzi M, Ozsoy M, Klingler HC, ''et al'', , , J. Urol., 2006
6. Pituitary magnetic resonance imaging in normal human volunteers: occult adenomas in the general population, Hall WA, Luciano MG, Doppman JL, Patronas NJ, Oldfield EH, , , Ann. Intern. Med., 1994
7. Pituitary incidentalomas, Molitch ME, , , Endocrinol. Metab. Clin. North Am., 1997
8. The significance of incidental thyroid abnormalities identified during carotid duplex ultrasonography, Steele SR, Martin MJ, Mullenix PS, Azarow KS, Andersen CA, , , Archives of surgery (Chicago, Ill. : 1960), 2005
9. Continuing controversies in the management of thyroid nodules, Castro MR, Gharib H, , , Ann. Intern. Med., 2005
10. Significance of incidental thyroid lesions detected on CT: correlation among CT, sonography, and pathology, Shetty SK, Maher MM, Hahn PF, Halpern EF, Aquino SL, , , AJR. American journal of roentgenology, 2006
11. Risk of malignancy in nonpalpable thyroid nodules: predictive value of ultrasound and color-Doppler features, Papini E, Guglielmi R, Bianchini A, ''et al'', , , J. Clin. Endocrinol. Metab., 2002
12. The significance of incidental thyroid abnormalities identified during carotid duplex ultrasonography, Steele SR, Martin MJ, Mullenix PS, Azarow KS, Andersen CA, , , Archives of surgery (Chicago, Ill. : 1960), 2005
13. Benign anatomical mistakes: incidentaloma, Mirilas P, Skandalakis JE, , , The American surgeon, 2002
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