Intranasal encephalocele: A case report

Abstract

Congenital midline nasal masses are rare anomalies. Nasal cerebral heterotopias (nasal gliomas) and nasal encephaloceles have an actual or potential central nervous system connection , and represent rare inborn malformations of the central nervous system . Nasal encephaloceles are herniations of the intracranial contents through a defect in the anterior skull base . Guthrie and Dott suggested that these lesions are not true cerebral herniations. It was concluded that the meningeal and brain protrusions exist first and that the bony defect is formed later . Nasal encephaloceles can be divided into two main groups: frontoethmoidal and basal encephaloceles . Basal encephaloceles can be classified as transethmoidal, sphenoethmoidal, transsphenoidal and frontosphenoidal. Frontoethmoidal and basal encephaloceles are very rare (1:5,000) . The pathogenesis of encephaloceles may be explained by a disturbance in the separation of the surface ectoderm and neurectoderm in the midline just after closure of the neural folds. It should be regarded as a "late" neurulation c&fjgct taking place during the 4th gestational week. Apoprosis appears to be related to this separation process. Diagnostic CT or MR imaging delineates the anatomy of the herniated mass .