Incidental findings are previously undiagnosed medical or psychiatric conditions that are discovered unintentionally and are unrelated to the current medical or psychiatric condition which is being treated or for which tests are being performed. Incidental findings may be uncovered in a variety of settings such as in test subjects during medical research, during the course of an autopsy, or during genetic testing.
The ethical issues around responding to incidental findings are complex.
An incidentaloma is a tumor found by coincidence which is often benign and does not cause any clinically significant symptoms; however a small percentage do turn out to be malignant. Incidentalomas are common, with up to 7% of all patients over 60 harboring 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.
Incidental findings in neuroimaging are common, with the prevalence of neoplastic incidental brain findings increasing with age.  Even in healthy subjects acting as controls in research incidental findings are not rare.
Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 15% of intracranial neoplasms. They often remain undiagnosed, and are often an incidental finding during autopsy. Microadenomas (<10mm) have an estimated prevalence of 16.7% (14.4% in autopsy studies and 22.5% in radiologic studies).
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