Nasal encephaloceles

Abstract

Nasal encephaloceles can be divided into frontoethmoidal and basal encephaloceles. Both conditions are very rare, but frontoethmoidal encephaloceles show a relatively high incidence (1:5,000) in Southeast Asia. The pathogenesis of encephaloceles may be explained by a disturbance in separation of surface ectoderm (epithelial layer) and neurectoderm (nervous tissue) in the midline just after closure of the neural folds. It should be regarded as a 'late' neurulation defect taking place during the 4th gestational week. Apoptosis appears to be related to this separation process. Frontoethmoidal encephaloceles can be recognized as a facial mass covered with normal skin, while basal encephaloceles may cause nasal obstruction or symptoms related to herniation of basal structures. Diagnostic CT or MR imaging delineates the anatomy of the herniated mass. Therapy for frontoethmoidal encephaloceles consists in excision of the cele, watertight closure of the dural defect and reconstruction of the skull defect. Basal encephaloceles may harbour vital herniated structures which should be saved. Hydrocephalus should be dealt with first, followed by elective single-stage reconstructive surgery. The prognosis appears to be better for patients with frontoethmoidal encephaloceles than for patients with occipital or parietal encephaloceles, and it depends largely on the presence of additional congenital anomalies of the brain. The differential diagnosis of a nasal mass must include nasal glioma, dermoid cyst, and nasal polyp.

Lumps and Bumps on the Head in Children: Use of CT and MR Imaging in Solving the Clinical Diagnostic Dilemma

“…These encephaloceles are more common in South and Southeast Asian populations (12). They are found projecting along the nasal bridge between the nasofrontal sutures into the glabella (nasofrontal region), under the nasal bones and above the nasal septum (nasoethmoidal region) (Fig 3), or along the medial orbit at the level of the frontal process of the maxilla and the ethmoid-lacrimal bone junction (naso-orbital region) (Fig 4) (7,8,12). Frontoethmoidal encephaloceles manifest as a clinically visible mass along the nose.…”

Nasal Encephalocoele: An Atypical Case

“…It should be regarded as a 'late' neurulation defect taking place during the 4th gestational week. 4 Basal and frontoethmoidal encephaloceles constitute a nasal subclass of encephaloceles, which are herniations from the skull base and ethmoid bone, respectively. Basal encephaloceles are usually occult and can herniate into nasal structures causing obstruction.…”

Prenatal detection and postnatal management of an intranasal glioma

“…Computed tomography is preferred for visualization of the internal and external bony defects [10]. However, in the first 6 to 8 months of life, the frontal, nasal, and ethmoidal bones are not ossified and have similar CT imaging attenuation as the brain and nasal cartilage, which may give the false impression that there is a bony defect in the frontonasal region [1,8].…”

“…However, in the first 6 to 8 months of life, the frontal, nasal, and ethmoidal bones are not ossified and have similar CT imaging attenuation as the brain and nasal cartilage, which may give the false impression that there is a bony defect in the frontonasal region [1,8]. Magnetic resonance imaging (MRI) provides more detailed information on the osseous frontonasal region in young infants, the CNS, the tissue characteristics of the mass, and its possible intracranial connection [7,8,10]. Besides, the lack of radiation most importantly in this usually very young patient population [6] and multiplanar imaging capacity favor the use of MRI [7,8].…”