Natural history and clinical management of optic pathway glioma.

Twenty-five consecutive unselected patients with optic pathway glioma (OPG) were primarily observed and treated if progression was evident. Diagnosis was based on MRI. The natural history of the OPG disease was more indolent in 12 patients with neurofibromatosis 1 (NF1) than in the others, and regressions were commonly observed. Thirteen non-NF1 patients had larger rumours at diagnosis and more progressions. There were five intra-orbital optic nerve tumours (one with progression), 19 chiasmatic tumours (12 with progression) and one diffuse tumour. OPG emerges before the age of 7 years in NF1 patients, and in non-NF1 patients also in older patients including adults. Progressive intra-orbital OPGs are best treated by surgical resection. Progressive chiasmatic tumours are best treated by radiotherapy and respond well by marked regression. Exceptionally, exophytic chiasmatic tumours may be treated by chiasm preserving surgery.