[Ganglioglioma of optic nerve in neurofibromatosis type 1. Case report and review of the literature].

Background: Gangliogliomas are rare tumors of the central nervous system. In only seven cases they have been found within the optic nerve. Two of these cases were associated with neurofibromatosis (NF), but a pathogenic link between gangliogliomas of the optic nerve and NF still remains controversial.

Patient: Here we report on a 71-year-old patient with a ganglioglioma of the optic nerves and NF type 1. Post mortem examination revealed multiple neurofibromas of the vagal and left femoral nerves, multiple schwannomas of the small bowel and Lisch noduli of both irides. In addition, a spindle shaped thickening of the right optic nerve was observed in its intracranial portion. The left optic nerve was normal on gross inspection.

Result: Histologically, tumoral tissue was found in both optic nerves. The tumor was composed of two cell types: highly differentiated, partly stellate, partly pilocytic astrocytes and, at the rim of the axon bundles of the optic nerve, fully developed synaptophysin- and neurofilament-antigen-positive ganglion-cells with short corkscrew-shaped processes. No mitosis could be found in the neuronal or in the glial cell population. In spite of the tumoral involvement of the optic nerves, there has been no evidence of visual disturbance.

Conclusion: Optic nerve tumors in NF most often are of glial origin (astrocytomas, pilocytic astrocytomas). Our case illustrates the rare condition of a glioneuronal tumor associated with neurofibromatosis type 1.