Heterotopic neural nodules of the scalp.

Congenital lesions of the scalp must be approached with caution because of the possibility of intracranial extension. Heterotopic neural nodules, a type of neuroectodermal malformation, are particularly dangerous. They manifest in the newborn as a small lump, are often confused with dermoid cysts, and may have a rudimentary stalk that communicates intracranially. The authors retrospectively reviewed the demographic, clinical, and histopathologic records of 11 infants with 12 heterotopic neural nodules of the scalp seen over the previous two decades. All lesions were located in the parietal or occipital region. All but one patient had an overlying area of alopecia surrounded by a ring of long, coarse hair (the "hair collar sign"), and nine of 11 children had a capillary stain surrounding the lesion. Preoperative imaging correctly identified calvarial defects in five patients. Excision was performed at an average age of 8.6 months. Histopathologic examination showed that nine lesions (nine patients) were heterotopic leptomeningeal tissue and three lesions (two patients) contained glial tissue. Heterotopic neural nodules of the scalp are rare congenital lesions with recognizable clinical and histologic features. Preoperative imaging is essential to document possible intracranial involvement and thus minimize possible penetration of the dura during resection.