Expert’s Corner: What to do about incidental imaging findings?

CT scan incidental finding imaging thyroid
Radiologists Edward Lee, MD, MPH, and Sarah Bixby, MD

The surge in computed tomography (CT) imaging in the last two decades has spurred an unintended consequence (apart from increasing patients’ radiation exposure)—an increase in the number of incidental findings, or incidentalomas. These worrisome, unanticipated spots on a scan might indicate malignancy or, as is more often the case, point to a benign finding.

Incidentalomas can be particularly troublesome for pediatric clinicians, says Edward Lee, MD, MPH, from Boston Children’s Hospital Department of Radiology. Lee and his colleagues Sara Vargas, MD, from Boston Children’s Department of Pathology, and Juan Baez, MD, from radiology, recently published the first research on pediatric incidentalomas, focusing on how to manage incidentally detected thyroid nodules on CT exams.

“In general, incidental findings in pediatrics are problematic because we don’t have criteria for how to manage them,” explains Lee, citing the conundrum presented by the dearth of relevant follow-up protocols. “So we extrapolate based on adult studies.”

Infrequent, but troubling

In the current study, the researchers reviewed chest CT studies performed between January 2006 and January 2013 and identified 35 patients with newly detected thyroid nodules.

Their goal was to determine prevalence and outcomes of the nodules. There are no clinical management guidelines related to incidentally detected thyroid nodules in children; sometimes patients undergo ultrasound studies, which may be followed by a biopsy. In other patients, the providers rely on clinical observation.

“[I]ncidental findings in pediatrics are problematic because we don’t have criteria for how to manage them.”

“We found that thyroid nodules aren’t that common in children, but when we do see them there is a higher likelihood the nodule is malignant,” says Lee.

Lee and Vargas recommend patients younger than 21 years old with a thyroid nodule be referred for an ultrasound exam which should be evaluated by a radiologist. If the ultrasound results are indeterminate or show worrisome features, the tissue should be aspirated or biopsied and evaluated by a pathologist.

Next steps

Vargas adds that referring providers should be open to seeking appropriate subspecialty expertise based on incidental findings. “This could put the patient into a different care pathway. The pediatrician may have planned to consult a pulmonologist, but if a thyroid nodule shows up, she may need to consult a radiologist or endocrinologist as well.”

The care path hinges on the type of incidental finding. If an incidental lung lesion is detected, for instance, the primary care provider should discuss its significance with the radiologist and also consult a pulmonologist. A urologist should be consulted if an incidental bladder obstruction is noted.

In the team’s thyroid study, 17 patients with incidentally detected thyroid nodules underwent follow-up ultrasound while 18 were followed clinically. Six of the ultrasound patients were referred for biopsy, and two of them, or 5.7 percent of those studied, were diagnosed with thyroid malignancies detected by biopsy.

Lee plans to continue research focused on refining pediatric imaging guidelines. In an upcoming study, for example, he and his colleagues will review outcomes for pulmonary nodules in children.

Learn more about Boston Children’s Department of Radiology.