B – 89 Navigating the Semantic Network: A case study of Awake Mapping and Resection of a Left Temporoinsular Glioma Presenting with Transient Transcortical Sensory Aphasia

Abstract Objective The temporoinsular region plays a pivotal role in semantic processing, object recognition, and naming, making it a critical node in the brain's language network. While transcortical sensory aphasia (TSA) is commonly associated with stroke, it is rarely described in neurosurgical populations. This case highlights how functional mapping during awake craniotomy can elucidate the neuroanatomical correlates of TSA and aid in safe tumor resection. Method A 44-year-old right-handed male presented with a left temporoinsular oligodendroglioma. He underwent awake craniotomy with Direct Electrical Stimulation (DES) to delineate language networks. Intraoperative tasks included picture naming, semantic and phonemic fluency, the Pyramid and Palm Trees test, and a dual-task paradigm. Stimulation of the supramarginal gyrus caused anomia, while dissection near the Inferior Fronto-Occipital Fasciculus (IFOF) induced semantic paraphasias. Repetition was intermittently assessed to delineate functional margins. Results Near-total tumor resection was achieved with transient postoperative TSA, characterized by fluent but semantically impaired speech, occasional perseveration, and relatively intact comprehension and repetition. These symptoms were consistent with transient disruption of temporoparietal semantic pathways. The patient demonstrated significant language recovery over the following weeks. Conclusion This case provides an unambiguous presentation of TSA in a neurosurgical context and illustrates the role of poly-etiologic factors—namely anatomical disruption and intraoperative mapping—in shaping outcomes. The findings highlight how detailed intraoperative neuropsychological monitoring can inform resection strategies and reinforce our understanding of the semantic network and its plasticity following surgical intervention.