Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease is an autosomal dominant disorder, caused by a mutation in the NF1 gene.

It is a multisystem disease, affecting the nervous, musculoskeletal, cardiopulmonary, integumentary, and other systems.

Focal areas of signal intensity (FASI), also known as unidentified bright objects (UBO) is the most common intracranial finding in patients with neurofibromatosis type 1 ¹.

Optic nerve gliomas may affect the optic nerves, the optic chiasm and optic tracts, so it is called optic pathway gliomas (OPG). It is usually unilateral and commonly shows fusiform enlargement of the optic pathway.

On MRI: the optic nerve glioma is:

• iso to hypointense onT1

• iso to hyperintense on T2

• the enhancement is variable on T1C+ (from absent to intense)

The diagnosis was confirmed by pathology (pilocytic astrocytoma, WHO grade I).