Preoperative mapping of Broca’s area through magnetoencephalography in an aphasia patient: A case report

Background: Preoperative identification of eloquent cortex is critical in patients with intracranial lesions involving the dominant hemisphere to minimize postoperative functional deficits. Case Description: This report presents a 45-year-old right-handed male with progressive expressive aphasia who was found to have a large left frontotemporal meningioma adjacent to the language cortex. Magnetoencephalography (MEG) was performed for functional mapping of language areas before surgical resection. During a silent word generation task, MEG source analysis demonstrated focal, left-lateralized activation in the inferior frontal gyrus, specifically within the pars opercularis and pars triangularis, consistent with Broca’s area, with peak activity at approximately 456 ms. In contrast, overt speech tasks predominantly activated bilateral sensorimotor cortices, reflecting articulatory motor function and limiting precise localization of language-specific regions. Integration of MEG data with neuronavigation enabled accurate intraoperative localization of the eloquent cortex. The patient underwent a left frontotemporoparietal craniotomy with Simpson grade I resection. Histopathology confirmed an atypical meningioma. Postoperatively, the patient demonstrated complete resolution of language deficits, and imaging confirmed preservation of Broca’s region without residual tumor. Conclusion: This case highlights the clinical utility of MEG in differentiating language-related cortical activity from motor speech execution and underscores its value in guiding safe resection of lesions adjacent to eloquent language cortex.