Separation of outer retinal layers secondary to selumetinib

New therapeutic agents targeting the mitogen-activated protein (MAP) kinase pathway, including MEK inhibitors, are currently being evaluated in phase 1 and 2 clinical trials for pediatric brain tumors. Ophthalmologic side effects from MEK inhibitors have previously only been reported in adults and included retinal vein occlusion, central retinal artery occlusion, and separation of the neurosensory retina. We report 2 patients with optic pathway gliomas who developed outer retinal layer separation visualized by optical coherence tomography while taking the MEK inhibitor selumetinib. After discontinuation of selumetinib, the outer retinal layer separation resolved without visual sequelae. One patient has been retreated with selumetinib and experienced recurrence of these findings.