So-called nasal glioma.

Nasal glioma is heterotopic brain tissue which usually presents as a tumor around the nose of children and infants. We have encountered two cases of nasal glioma during the past nine years at Hokkaido University Hospital. One showed a tumor in the subcutis of the nasal bridge and the other a polypoid mass arising in the soft palate. Both consisted of proliferation of fibrillary spindle cells consistent with fibrillary astrocytes divided by fibrovascular septa. This was reminiscent of "gliosis" of the central nervous system. Occasional protoplasmic astrocytes were present in both and, in addition, one case showed neuronal cells and choroid plexus. The glial nature of the lesion was confirmed by the presence of glial fibrillary acidic protein demonstrated by the immunoperoxidase method. Nasal glioma is not neoplastic contrary to its name and is considered heterotopic brain tissue which was displaced during fetal development by similar pathogenetic mechanisms of sincipital and basal encephalocele, although its communication to the brain was lost.