MRI and clinical differences between optic pathway tumours in children with and without neurofibromatosis

Abstract

The purpose of this study was to evaluate the value of MRI in studying optic pathway tumours associated with neurofibromatosis, and to look for potentially helpful criteria for the management of such lesions. This retrospective study included 14 children with neurofibromatosis type 1 (NF-1) as well as a lesion of the optic pathway. Clinical data and MRI findings were analysed with regard to location, structure and course of the tumours, and were compared with 13 optic pathway tumours in patients without NF-1. The median age of onset was 4.1 years. 11 patients with NF-1 were asymptomatic. In the NF-1 group, the optic nerves were involved in 10 cases without a cystic component at the time of diagnosis. In the non-NF-1 group, the tumour was located in the chiasma in 11 cases; 12 cases had a cystic component. 10 of the NF-1 group had no tumour progression over an average follow-up of 3.2 years without treatment. These findings suggest that optic astrocytomas in association with NF-1 are distinct lesions from isolated optic gliomas. In NF-1, most such tumours show only slight progression, and may correspond to perineural gliomatosis rather than a true pilocytic astrocytoma. Among NF-1 patients, initial MRI provides no prognostic criteria in children who subsequently show tumour progression. Nevertheless, MRI can be useful in establishing the diagnosis of NF-1 and can serve as a baseline study.

Distinct Genetic Signatures among Pilocytic Astrocytomas Relate to Their Brain Region Origin

“…The observation that NF1-PAs tend to be clinically less aggressive, particularly when located in the optic pathway (2,25), coupled with the finding that NF1 inactivation is only found in NF1-PAs, suggests that NF1-PAs have a unique set of genetic changes in addition to NF1 loss. Using SAM analysis to identify transcripts differentially expressed in NF1-PA compared with sporadic PA, we found a limited number of NF1-PA-specific transcripts, all of which were up-regulated relative to sporadic PA. A few of these differentially expressed transcripts have known functions (CUGBP2 and SLC1A3 or GLAST; refs.…”

Diagnosis and management of optic nerve glioma

“…4,13 Chiasmal and post-chiasmal tumours are more common in sporadic cases whereas gliomas limited to the optic nerve occur more frequently in patients with NF1. 14,15 Bilateral optic nerve gliomas without chiasmal involvement is virtually diagnostic of NF1. 9,12,16 Most of the current literature reports a roughly equal sex ratio in sporadic childhood optic nerve gliomas; 1,4,17 however, recent studies suggest a distinct female preponderance in patients with NF1.…”

Glioma de nervio óptico en un caso de neurofibromatosis-1 infantil

“…To end, we emphasize the high frequency of optic pathway gliomes in children with neurofibromatosis type 1, being tumors with good prognosis, better than in adults or subjects without the disease (5). Likewise, the role of the ophthalmologist also seems important because it is crucial in the initial assessment and follow-up.…”