A cavernous malformation presenting with homonymous superior quadrantanopia

Abstract

Cerebral cavernous malformations (CMs) are vascular lesions that may remain asymptomatic but can cause neurological deficits when located in eloquent brain regions. Retrochiasmal visual pathway involvement is rare, and isolated homonymous quadrantanopia is exceptionally uncommon. A 64-year- old woman presented with a one-year history of progressive visual disturbance. Automated perimetry demonstrated bilateral, congruous superior quadrantanopia with well-demarcated defects. Magnetic resonance imaging revealed a well-circumscribed ovoid lesion in the medial right anterior temporal lobe, adjacent to the roof of the temporal horn. The lesion exhibited mixed T2 signal, a hypointense hemosiderin rim, and prominent susceptibility blooming, consistent with a cavernous malformation. Its location corresponded to Meyer’s loop, the anterior portion of the optic radiation, explaining the congruous superior quadrantanopia. Reports of CMs resulting in visual field loss are exceedingly rare. This case uniquely demonstrates unequivocal involvement of Meyer’s loop, yielding a congruous superior quadrantanopia and expanding the clinical spectrum of CM presentations.