Congenital geniculate quadruple sectoranopia with occipital heterotopia

Abstract

Purpose: To report a case of congenital geniculate quadruple sectoranopia associated with occipital heterotopia.

Observations: A 51-year-old healthy woman was incidentally found to have a left incongruous quadruple sectoranopia. Analysis of the macular ganglion cell complex (GCC) revealed homonymous hemianopic thinning of the inner layer of the retina. Brain magnetic resonance imaging (MRI) showed congenital occipital heterotopia, characterized by hypertrophy of the right parahippocampal gyrus, lingual gyrus, and isthmus of the cingulate gyrus, with shrinkage of the white matter. In addition, serial coronal images on a short tau inversion recovery (STIR) sequence demonstrated an atrophic right optic tract.

Conclusion and importance: Congenital geniculate quadruple sectoranopia is extremely rare and may be caused by congenital occipital heterotopia.

Keywords: Geniculate hemianopia; Incongruous homonymous hemianopia heterotopia; Quadruple sectoranopia; lateral geniculate nucleus.

Fig. 1

Fundus photos and SD-OCT images. A) Fundus photographs showed large cups in both optic discs. B) RNFL analysis showed slight nasal and temporal thinning on the left and normal thickness on the right. C) Analysis of the macular GCC revealed the homonymous hemianopic thinning of the inner layers of the retina. RNFL, retinal nerve fiber layer; GCC, ganglion cell complex; SD-OCT, spectral-domain optical coherence tomography; GCL, ganglion cell layer; IPL, inner plexiform layer.

Fig. 2

A 30-2 Humphrey automated visual field examination demonstrating a left incongruous quadruple sectoranopia. The superior and inferior sectorial visual field defects along the vertical meridian spare the horizontal macular zone and consist of larger visual field defect in the left eye.

Fig. 3

MRI of the brain. A) Axial T1-weighted MRI image of the brain demonstrated nodular hypertrophy of the right parahippocampal and lingual gyri and isthmus of the cingulate gyrus (arrows), in contrast with shrinkage of the white matter surrounding the right lateral ventricle trigone toward the posterior horn. There was no enhancement of the lesion after gadolinium injection. B) Serial coronal images (thickness, 2.5mm) on a short tau inversion recovery (STIR) sequence revealed the optic tracts anterior to the LGN (arrows). Note that the right optic tract is thinner than the left optic tract.

Fig. 4

The diagram depicts the right LGN laminae in mid-coronal section viewed from front. The outer lamina receives the crossed projection from contralateral retina (Laminae 6,4, and 1), whereas the laminae receiving the uncrossed retinal projection occupy the core of the nucleus (Laminae 5,3, and 2). The postulated lesion in our case involves the external portion of the lateral horn, which mainly comprises lamina 6 receiving crossed projections from the contralateral lower peripheral retina and a large area of the medial horn receiving projections from upper hemiretinas of both eyes (shaded area).