Objective. To call attention to a cutaneous marker for neural tube clo
sure defects of the scalp, the ''hair collar'' sign. This finding cons
ists of a ring of long, dark, coarse hair surrounding a midline scalp
nodule. Methods and Results. Four children with small congenital scalp
nodules and the hair collar sign were studied from the standpoint of
clinical findings, radiologic scans, and histology of the excised nodu
les. All four had an overlying vascular stain in addition to the hair
collar. Patients 1 and 2 were found to have encephaloceles, and one ha
d heterotopic brain tissue. The fourth family refused surgery, but the
clinical and radiologic findings were consistent with a diagnosis of
atretic encephalocele. One infant had agenesis of the corpus callosum
and a Dandy-Walker malformation as associated findings. Conclusions. T
he ''hair collar'' sign should alert the pediatrician to the possibili
ty of ectopic neural tissue in the scalp and/or underlying central ner
vous system malformations.