Large optic nerve glioma with normal vision

Visual prognosis of optic glioma

BACKGROUND

Optic gliomas may unpredictably stabilize or progress. Prognosis was known to be better in patients with neurofibromatosis 1 (NF1) than those with non-NF1. The confusion over management is caused, at least in part, by the uncertain disease course of the tumor.

CASE HISTORY

We report here a 13-year-old girl presented with a 1-month history of a gradual decline of vision in her left eye. She was diagnosed by clinical examination and magnetic resonance imaging as having a left optic-nerve glioma and was followed by serial magnetic resonance imaging over 3 years. She and her family did not show any stigmata of NF1. Approximately 3 years after the onset of her symptoms, visual acuity, color testing, and visual fields have markedly improved with tumor regression by magnetic resonance imaging.

CONCLUSIONS

The possibility of spontaneous regression of an optic-nerve glioma should be considered even in the planning of treatment for a non-NF1 patient with this tumor.

Fractionated stereotactic radiotherapy (FSRT) for optic glioma

PURPOSE

To determine efficacy and toxicity of fractionated stereotactic radiotherapy (FSRT) in patients with optic glioma.

METHODS AND MATERIALS

Ten patients suffering from optic glioma were treated by FSRT between December 1990 and December 1995 at the German Cancer Research Center (DKFZ) in Heidelberg. Eight patients were treated for progressive recurrent tumor following partial tumor resection and 2 patients were treated postoperatively. Dose distributions were calculated by a 3D treatment planning system (Voxelplan, Heidelberg). Patients were treated with a noninvasive repeatable stereotactic fixation system using a manually driven midsize multileaf collimator attached to a linear accelerator. We applied a median prescribed total dose to the isocenter of 52.4 Gy with a median daily fraction size of 1.8 Gy.

RESULTS

All patients treated by definitive radiotherapy remained free from local tumor progression during the follow-up period (range 12-72 months) except the 1 patient treated for recurrence after previous radiotherapy. A complete remission was achieved in 3 patients with subsequent improvement of visual acuity. None of the patients with locally controlled tumor experienced any further impairment of vision. One patient developed new ACTH deficiency. No other clinically significant late effects attributable to radiotherapy were observed.

CONCLUSION

FSRT permits treatment of optic glioma with excellent tumor control and without clinically relevant morbidity. Compared to conventional techniques there is the potential of sparing the pituitary gland in chiasmatic lesions.

Gliomas of the anterior visual pathway

Gliomas of the anterior visual pathway are rare orbital lesions accounting for 65% of all intrinsic optic nerve tumors. These lesions occur principally among children in the first decade of life. They appear to be true neoplasms that characteristically show early growth, followed by stability in many patients. Visual prognosis is fair, and the outlook for life depends upon tumor location. When initially confined to the optic nerve alone, overall mortality is about 5%. Once the hypothalamus is involved, mortality rises sharply to over 50%. With involvement of the chiasm or hypothalamus, no form of therapy significantly alters the final outcome. Because of their indolent course, gliomas may be followed conservatively when confined to the optic nerve. In these cases, surgery is indicated only when blindness and pain or severe proptosis intervene. However, all such patients should be followed radiologically for evidence of posterior extension. When the chiasm is threatened, surgical excision via a craniotomy approach is warranted to prevent subsequent hypothalamic or third ventricle involvement. Malignant optic glioma is a distinct disease primarily affecting middle-aged adults. The chiasm is always involved, and although one eye may be spared initially, rapid progression to bilateral blindness is usual. The disease is uniformly fatal.

Optic atrophy

A young woman became suddenly aware of visual loss in her left eye. She was found to have optic atrophy giving chronicity to the disease process. A hypopigmented macule on her face along with neuroimaging studies suggested an inflammatory process. A biopsy of the skin lesion was compatible with sarcoidosis. The patient responded to corticosteroid therapy.

Combined clinical and computed tomographic diagnosis of orbital glioma and meningioma

The clinical information on 22 patients with orbital optic nerve gliomas and 47 patients with meningiomas was correlated with computed tomographic findings obtained in both axial and coronal studies. Most of the gliomas occurred in children, although 7 patients presented after 20 years of age. Among the patients with meningiomas, the majority were women in early middle age, although two tumors occurred in children less than 20 years of age. Low grades of proptosis (median, 2 mm for both tumors), frequent significant visual field obscurations with eye movements, and opto-ciliary shunt vessels pointed toward the diagnosis of an optic nerve tumor. Patients with gliomas generally manifested massively swollen fusiform optic nerves with clear-cut margins due to circumscription by an intact dura. Kinks and bucklings of the optic nerve as well as infarctive cysts distinguished the glioma CT-scan patterns from the meningiomas. Distinctive axial CT-scan features of the meningiomas not shared by the gliomas were narrowly and diffusely enlarged nerves with polar expansions either at the orbital apex or immediately behind the globe; calcification; irregular excrescent margins signifying extradural invasion into the orbital soft tissues; a negative optic nerve shadow running down the center of the lesion; and bone erosion near the orbital apex. Coronal studies often revealed irregular margins signifying transgression of the dura. A diffusely and narrowly enlarged optic nerve shadow with regular margins (intrasheath lesions) was the one morphologically overlapping pattern displayed by 11 meningiomas and three gliomas. In these cases there tended to be more profound visual loss in the gliomas compared with the meningiomas, as well as the more frequent presence of opto-ciliary vessels in the meningiomas. Arteriography may be helpful in this particular category by demonstrating a tumor blush for the meningiomas, whereas this finding is typically absent with optic nerve gliomas. Meningiomas may be very closely simulated by dural or intraneural inflammations.