Incidentalomas and the Cascade Effect
In the startling strange world of modern imaging we continue to be stunned by the unexpected. As more and more people are subjected to CT, MRI and ultrasound scanning, a plethora of unexpected or serendipitous findings are revealed. If only we had the knowledge and wisdom to ignore most of these incidental findings, how many untold patients, their families, and physicians would sleep more soundly at night?
The typical surprise finding is that of an unexpected mass, the quaintly but appropriately named incidentaloma. Many physicians are unaware of the frequency of these masses in the general population. For example, up to 10% of the population harbors a cyst or benign cortical adenoma of the adrenal gland; these are picked up on CT or MRI scanning of the abdomen. Benign fluid-filled (cystic) masses are frequently seen in the breast, thyroid, kidney, liver, spleen, pancreas, and pituitary gland. Unexplained "bright spots" in the brain can be seen in a large percentage of otherwise normal MRIís. One of the more common clinical examples of an incidentaloma is a cystic or solid mass the thyroid nodule, 99% of which are clinically meaningless. Another interesting statistic: Up to half the population over age 50 has cysts of the kidney.
When some unexpected finding is reported on an imaging study, what is to be done? Common sense and a knowledge of the frequency and location of these findings often saves untold anxiety, expense, even risk, but far too often, the discovery of an incidentaloma is one of the more noxious byproduct of modern medical science.
The problem of abnormal or incidental findings leading to an uncontrollable series of unforeseen events, is described as The Cascade Effect. Such findings, found on routine exams, often on screenings, frequently result from ill-advised diagnostic testing, and are almost always without medical significance. Yet they can result in a series of extensive and risky diagnostic procedures culminating in clinical catastrophes.
Cascade fiascos are frequently catalyzed by anxiety on the part of the patient or his physician, and are becoming increasingly more common in clinical practice because of the introduction of new and ever more pervasive technologies along with unjustified medical testing. Hereís a single example, but I have encountered many, many more.
A 35 year old nurse underwent abdominal ultrasound for vague GI symptoms. The study was negative except for the incidental discovery of a small liver "lesion." She was told, "It might be serious," and a biopsy was suggested. Over the next several weeks she developed a serious depression, and consulted a psychiatrist. A CT was nondiagnostic, so she ended up having hepatic angiography, an invasive procedure, not without risk, in which dye is injected into a major artery leading to the liver. A diagnosis of "benign hemangioma" was finally made. This is a tiny localized collection of blood vessels seen in over 2% of the population. Later review of the ultrasound study showed a typical diagnostic pattern.
Medical Cost: $8,500, including psychiatrist. Emotional Cost: Impossible to estimate.
Martin F. Sturman, MD, FACP
Copyright 2007, Mathemedics, Inc.
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