Reviewing brain MRI of close to 4,000 children as part of an ongoing population-based study, European neuroradiologists and neuroscientists discovered at least one incidental finding in more than one-quarter of the cohort.

The vast majority of the lesions turned out to be cysts and other benign abnormalities, but there were enough suspected and confirmed tumors—all asymptomatic—to prompt the study authors to advise the adoption of standardized protocols.

The researchers, representing three universities in the Netherlands, report their findings in a research letter published Oct. 19 in the New England Journal of Medicine.

Philip Jansen, MD, of Erasmus University Medical Center in Rotterdam and colleagues interpreted scans of 3,966 children (mean age, 10.1 years; range, 8.6 to 11.9) who underwent brain MRI on a 3T scanner as part of the Generation R Study.

They reported at least one incidental finding in 25.6 percent of the children.

While only 17 of the findings (0.43 percent) called for clinical follow-up, seven of the children (0.18 percent) had suspected primary brain tumors.

Two of these diagnoses were confirmed upon histopathological exam, and the children underwent neurosurgical treatment.

The authors note that the prevalence of asymptomatic brain tumors in their population-based cohort was higher than estimates from cancer registries. In the U.S., they point out, the prevalence is estimated at around 35 in 100,000 (0.04 percent) among individuals younger than 20 years of age.

However, no reliable statistics are available to estimate the frequency of asymptomatic brain tumors among children, they add.

“Our results emphasize the need for careful evaluation of incidental findings on brain scans of asymptomatic children,” Jansen et al. conclude. “In addition, it may be prudent to use standardized protocols for managing incidental findings in children, including reporting, disclosure to parents and subsequent follow-up when necessary.”