Nasal heterotopia versus pilocytic astrocytoma: A narrow border.

Failure of the anterior neuropore can lead to three main types of anomalies: nasal dermal sinus, encephalocele and nasal glioma or heterotopia. In this report, we describe a case of intracranial and extracranial glial heterotopia that probably resulted from a common failure of anterior neuropore development. We describe the prenatal radiological assessment based on ultrasound and MRI results, and consider their limitation for early fetal diagnosis. We also discuss the embryogenesis and the possible pathogenic mechanisms involved.