Optic nerve anomalies in basal encephalocele.

Basal encephalocele should be suspected in child when hypertelorism, defect of the bridge of the nose, and other midfacial anomalies are present. Optic nerve anomalies may occur with basal encephalocele. Those previously described are pale discs, coloboma of the optic nerve head, and pit of the optic disc. Two additional disc anomalies that are associated with basal encephalocele are megalopapilla and optic nerve dysplasia. A mass in the nose or nasopharynx under these circumstances is most likely an encephalocele and biopsy is contraindicated.