Morning Glory Disc Anomaly With Ipsilateral Carotid Vasculopathy: MRI Characteristics and Clinical Implications.

Morning glory disc anomaly (MGDA) is a rare developmental malformation of the optic nerve that can complicate the diagnosis and treatment of children. We describe a case of a three-year-old girl who presented with a reduction of vision and an exotropia of the right eye. Fundoscopic observation revealed evidence of MGDA, which was confirmed through magnetic resonance imaging (MRI). MRI showed the characteristic triad of orbital appearances: a funnel-shaped morphologic structure of the posterior optic disc and elevation of the adjacent retinal surface, abnormal tissue surrounding the ipsilateral optic nerve distal part with obliteration of the surrounding subarachnoid spaces, and discontinuity of the uveoscleral coat. Post-contrast imaging revealed enhancement in the distal retrobulbar optic nerve area, likely representing displaced choroidal tissue accompanied by glial and fibrous proliferation. Notably, MR angiography showed narrowing of the right internal carotid artery segments (petrous, cavernous, and supraclinoid) with a hypoplastic right A1 segment. This represents an intermediate vascular phenotype--significant vasculopathy without the collateral vessels that define Moyamoya disease. This case highlights the importance of comprehensive neuroimaging in MGDA patients, as early identification of associated vascular anomalies is crucial for appropriate surveillance and management. The consistent MRI findings described can aid in differentiating MGDA from other ocular anomalies, particularly optic nerve coloboma, which has different genetic and prognostic implications.