Anterior visual pathway gliomas

The benign anterior visual pathway glioma undoubtedly is the most controversial subject in neuro-ophthalmology. Although we are persuaded by the evidence that they are true neoplasms rather than hamartomas, the controversy over their biological nature seems moot, as they have a low growth potential. That is not to say that serious visual loss is not common or that, in some cases (especially among those lesions arising in the chiasmalhypothalamic region), tumor-related death and disability cannot occur. These posteriorly located lesions may cause hydrocephalus, and shunting is required if that occurs. The need for shunting in such cases may be the only point on which experts agree. What has yet to be established is whether any of the forms of therapy now available for anterior visual pathway gliomas without hydrocephalus is better than no treatment. Surgery, radiation, and chemotherapy all carry risks. A randomized, controlled study, if feasible, would be apt to settle the issue. The low incidence of these tumors might frustrate attempts to complete such an investigation in a reasonable period. A team of physicians should manage patients with benign anterior visual pathway gliomas. Radiologists, neurologists, neurosurgeons, radiation oncologists, pediatricians, endocrinologists, and oncologists all have a role, but the neuro-ophthalmologist should be the leader. Neuro-ophthalmologists are in the unique position of being able to recognize and document changes in the patient's visual function. Furthermore, neuro-ophthalmologists, being disinterested, are free to choose without bias from among the various management options. The malignant anterior visual pathway glioma is not a subject of controversy. The clinical features at presentation are apt to be misinterpreted as evidence of an inflammatory or ischemic neuropathy rather than the announcement of a fatal brain tumor. Though these patients receive radiotherapy and chemotherapy, these measures have not improved survival significantly, and the outcome is uniformly fatal. The only positive thing that can be said about the malignant gliomas of the anterior visual pathway is that they are so rare.