Hemorrhagic Intracranial Cavernoma Presenting as a Homonymous Horizontal Sectoranopia

Area of Science:

• Neuro-ophthalmology
• Neuroimaging
• Neuroanatomy

Background:

• Hemorrhagic insults to the lateral geniculate nucleus (LGN) are uncommon, often linked to vascular malformations, tumors, or trauma.
• Accurate localization of LGN lesions is crucial and often guided by characteristic visual field defects.

Observation:

• A young woman presented with sudden, painless left homonymous horizontal sectoranopia.
• MRI revealed a right temporal lobe hemorrhagic cavernous malformation.
• Optical coherence tomography (OCT) and Humphrey perimetry confirmed the lesion's location in the right LGN.

Findings:

• OCT demonstrated a unique pattern of right homonymous sectoranopia in macular ganglion cell-inner plexiform layer (mGCIPL) thinning.
• This thinning was contralateral to the visual field defect, indicating retrograde neuroaxonal degeneration.
• The specific OCT pattern suggested injury to the posterior lateral choroidal artery supplying the LGN.

Implications:

• This case underscores the utility of OCT in precisely localizing LGN lesions by identifying characteristic patterns of mGCIPL thinning.
• The findings highlight the correlation between the anatomical location of visual pathway lesions and functional deficits.
• It emphasizes the diagnostic value of correlating neuroimaging, visual field testing, and OCT in complex neuro-ophthalmic cases.