nasal glial heterotopia
Nasal gliomas, also known as nasal glial heterotopia, are a rare congenital lesion composed of dysplastic glial cells which have lost their intracranial connections and present as an extranasal or intranasal mass.
Epidemiology
Nasal gliomas are rare congenital lesions. These masses occur sporadically with no familial tendency or gender predilection .
Clinical presentation
Extranasal gliomas clinically present in early infancy or childhood as a firm, red to bluish skin-covered mass. These masses will not exhibit pulsations or increase in size with the Valsalva maneuver or compression of the ipsilateral jugular vein (Furstenberg sign).They are typically slow growing; however, they may grow more or less rapidly than the adjacent soft tissue.
Intranasal gliomas present as large, firm, submucosal masses that extend inferiorly, toward or near the nostril. They can cause:
- obstruction of the nasal passage
- respiratory compromise in infants
- obstruction of the nasolacrimal duct, with resultant epiphora
- cerebrospinal rhinorrhea
- meningitis
- epistaxis
Pathology
Nasal gliomas are composed of dysplastic glial tissue and are congenital non-neoplastic lesions best categorized as heterotopia. They are rarely associated with other congenital malformations . A nasal glioma may be connected to the brain by a stalk of tissue in up to 15% of cases, but the stalk does not contain a direct fluid-filled tract that communicates with the subarachnoid spaces; therefore, a nasal glioma is distinct from a nasal encephalocele.
Location
They can be subdivided into:
Nasal gliomas occur near the root of the nose (where the cranial portion of the nose joins the forehead). Extra-nasal gliomas are usually seen in a paramedian location at the bridge of the nose external to the nasal passage, whereas intranasal lesions are usually located within the nasal passage medial to the middle turbinate bone.
Radiographic features
Ultrasound
Ultrasound is useful for determining if the mass is cystic or solid. Doppler flow studies of nasal gliomas reveal a characteristic low arterial flow velocity during the end-diastolic phase .
MRI
Nasal gliomas are often isointense relative to the normal brain at MR imaging, which is the imaging modality of choice. High-resolution surface coil MR imaging is often useful in demonstrating the intracranial stalk.
Treatment and prognosis
Once the diagnosis of a nasal glioma is established, early surgical resection is advocated to prevent local recurrence, nasal deformity, and secondary visual involvement . Surgical resection is often curative .
Differential diagnosis
Differential diagnosis include:
- encephalocele
- neurogenic tumors
- ectodermal tumors
- mesodermal tumors
- teratomas
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