Prosopagnosia following nonlanguage dominant inferior temporal lobe low-grade glioma resection in which the inferior longitudinal fasciculus was disrupted preoperatively: illustrative case

Abstract

Background: Prosopagnosia is a rare neurological condition characterized by the impairment of face perception with preserved visual processing and cognitive functioning and is associated with injury to the fusiform gyrus and inferior longitudinal fasciculus (ILF). Reports of this clinical impairment following resection of right temporal lobe diffuse gliomas in the absence of contralateral injury are exceedingly scarce and not expected as a complication of surgery.

Observations: The authors describe the case of a young female patient found to have an incidental diffuse glioma in the right inferior temporal lobe despite evidence of preoperative ILF disruption by the tumor. Following resection of the lesion, despite the preoperative disruption to the ILF by the tumor, the patient developed prosopagnosia. There was no evidence of contralateral, left-sided ILF injury.

Lessons: Given the significant functional impairment associated with prosopagnosia, neurosurgeons should be aware of the exceedingly rare possibility of a visual-processing deficit following unilateral and, in this case, right-sided inferior temporal lobe glioma resections. More investigation is needed to determine whether preoperative testing can determine dominance of facial-processing networks for patients with lesions in the right inferior posterior temporooccipital lobe and whether intraoperative mapping could help prevent this complication.

Keywords: DTI = diffusion tensor imaging; IFOF = inferior frontal occipital fasciculus; ILF = inferior longitudinal fasciculus; LGG = low-grade glioma; MRI = magnetic resonance imaging; diffusion tensor imaging; glioma; inferior longitudinal fasciculus; prosopagnosia; temporal lobe.

FIG. 1.

A: Preoperative films demonstrating a T2 hyperintense lesion in the posterior inferior temporal gyrus and fusiform gyrus. B: Preoperative DTI showing disruption of the right ILF preoperatively but residual fibers are still present in the white matter fasciculus. C: Resection cavity is present within the right inferior temporal gyrus with small volume blood and a small region of cytotoxic edema along the superior medial margin of the resection cavity. D: Postoperative DTI showing additional transection of the ILF in the inferior temporal gyrus and fusiform gyrus. FLAIR = fluid-attenuated inversion recovery.

FIG. 2.

Postoperative diffusion-weighted imaging demonstrating minimal reduced diffusion surrounding the resection cavity.