Brain, spine MRI may help detect melanocytic nevi in children

Brain and/or spinal MRI were effective in detecting melanin in the central nervous system of children with suspected central nervous system abnormalities, according to study findings.

“High-risk congenital melanocytic nevi are associated with abnormalities of the central nervous system, prompting MRI screening guidelines,” Holly Neale, MD, of the departments of dermatology at the University of Massachusetts Medical School and Massachusetts General Hospital, and colleagues wrote.

In the retrospective review, the researchers described MRI brain and spine abnormalities in children with this condition. Trends in nevus features were assessed, along with MRI findings and neurologic outcomes for the 352 patients in the study population.

Eligible participants were aged 18 years or younger and had at least one nevus diagnosed by a dermatologist.

Results showed that 46 children reported congenital melanocytic nevi that led to an MRI of the brain and/or spine. Half of these patients were male, with an average age at first image of 354.8 days.

Melanin was detected in the central nervous system (CNS) of eight of these 46 children. In addition, all of the children with melanin in the CNS had more than four congenital melanocytic nevi.

There was one fatal brain melanoma among these patients.

“Concerning” imaging results were observed in four patients who did not have melanin in the CNS.

Compared with children with normal imaging results, neurodevelopmental problems were more common in participants with concerning MRI findings, as were seizures, neurosurgery and death.

Further data showed that 306 patients underwent MRIs for other reasons. No melanin was detected in these patients.

Among 15 children with multiple small congenital melanocytic nevi, none had concerning imaging results.

The small sample size, lack of control arm and retrospective nature of the study may limit the applicability of the findings, according to the researchers.

“MRI of the brain and spine is useful for detecting intervenable abnormalities in high-risk children,” the researchers concluded. “Healthy infants with few small [congenital melanocytic nevi] may not require screening MRI.”