A Discussion of a Case of Paradoxical Ipsilateral Hemiparesis in a Patient Diagnosed with Pterional Meningioma

<b>Background:</b> Although various theories have been developed to explain ipsilateral hemiparesis, the causes behind this clinical phenomenon are still poorly understood. The main pathophysiological hypotheses include the anatomical variations in decussation of the corticospinal tract, the theory of diaschisis, the Kernohan-Woltman notch phenomenon, and Ectors' syndrome. The current article aims to report the case of a 43-year-old woman diagnosed with ipsilateral hemiparesis following a right pterional meningioma, later treated by surgery. The different theories behind this paradoxical clinical phenomenon are discussed to elucidate the most likely mechanism behind it. <b>Methods:</b> A 43-year-old right-handed woman with a history of splenomegaly and iron deficiency anemia was admitted to our hospital for refractory headache, right-sided hemiparesis, and generalized tonic-clonic seizures. Clinical examination revealed a right upper motor neuron syndrome, with a grade 4 MRCS muscle strength for the upper and lower limbs. The contrast-enhanced brain MRI revealed an extra-axial right pterional mass lesion with a broad dural base, well-defined margins, and intense post-contrast enhancement, suggestive of meningioma. The patient was surgically treated for the brain lesion. <b>Results:</b> After a Simpson grade I resection with complete removal of the tumor and affected dura, the patient had a favorable local and neurological evolution, and after three weeks, total remission of the symptoms was achieved. <b>Conclusions:</b> To assess the mechanism behind ipsilateral hemiparesis, thorough clinical examination and further research in neuroimaging assessment and functional studies are essential.