The hair collar sign: marker for cranial dysraphism.

OBJECTIVE: To call attention to a cutaneous marker for neural tube closure defects of the scalp, the "hair collar" sign. This finding consists 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 nodules. All four had an overlying vascular stain in addition to the hair collar. Patients 1 and 2 were found to have encephaloceles, and one had heterotopic brain tissue. The fourth family refused surgery, but the clinical and radiologic findings were consistent with a diagnosis of atretic encephaloceles. One infant had agenesis of the corpus callosum and a Dandy-Walker malformation as associated findings.

CONCLUSIONS: The "hair collar" sign should alert the pediatrician to the possibility of ectopic neural tissue in the scalp and/or underlying central nervous system malformations.