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. more...
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 (Grumbach et al 2003).
Autospy 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 (Hall et al). When encountering such a lesion, long term surveillance has been recommended (Molitch). Also baseline pituitary hormonal function needs to be checked, inculding measurements of serum levels of TSH, prolactin, IGF-I (as a test of growth hormone activity), and adrenal function (i.e. dexamethasone suppression test).
Other organs that can harbor incidentalomas are the liver (often a hemangioma), thyroid, parathyroid, and the kidneys.
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." (Miralas et al) The underlying pathology shows no unifying histological concept.
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