Nasal glial heterotopia Nasal glial heterotopia Nasal glial heterotopia refers to congenital malformations of displaced normal, mature glial tissue, which are no longer in continuity with an intracranial component. This is distinctly different from an encephalocele, which is a herniation of brain tissue and/or leptomeninges, that develops through a defect in the skull, where there is a continuity with the cranial cavity. While nasal glial heterotopia (NGH) is the preferred term, synonyms have included nasal glioma. However, this term is to be discouraged, as it implies a neoplasm or tumor, which it is not. By definition, nasal glial heterotopia is a specific type
Nasal glial heterotopia there is a large amount of associated fibrosis. The lesions are usually <2 cm in greatest dimension. A trichrome stain will highlight the dual components well, with the glial tissue staining red, while the background fibrosis stains a bright blue. The glial tissue is highlighted with S100 protein and with glial fibrillary acidic protein, although the latter is much more sensitive for glial tissue. The most common missed lesion is within the nasal cavity, where a fibrosed nasal polyp may be considered. However, it does not have glial tissue. Further, a polyp usually has mucoserous glands. The lesion is frequently