The Hemispheric Imbalance: A Double Encounter with Dyke-Davidoff-Masson Syndrome.

This article aims to present and interpret two instances of Dyke-Davidoff-Masson syndrome (DDMS), with the main features of cerebral hemiatrophy and compensatory skull changes, focusing on the clinical spectrum, imaging features, and variations in timing of presentation. Two male patients with left cerebral hemisphere involvement were evaluated. The first case was an 8-year-old child presenting with intellectual disability, delayed milestones, right hemiparesis, abnormal jerky movements, and generalized seizures. The second case was a 22-year-old adult with hemiparesis and generalized seizures since birth. Both underwent detailed neurological examination and magnetic resonance imaging (MRI) on a 3T scanner, including time-of-flight (TOF) angiography to assess cerebral vasculature. MRI of the first patient demonstrated left cerebral hemiatrophy with dilatation of the ipsilateral lateral ventricle and sulcal prominence, mild falcine deviation toward the affected side, and compensatory hypertrophy of the left calvarial bones (temporal, parietal, frontal, occipital) with enlargement of the frontal sinus and mastoid air cells and elevation of the left petrous ridge. Mild attenuation of the left middle cerebral artery (MCA) segments was seen on TOF imaging. The second patient's MRI revealed left cerebral hemisphere atrophy with gliosis in the MCA territory, left ventricular dilatation, ipsilateral sulcal prominence, and a neuroglial cyst in the left insular cortex with similar bony changes as those of the previous patient. TOF angiography showed attenuation of the left MCA segments without filling defects. DDMS is associated with a certain specific set of clinical and radiological features. Early recognition through MRI and computed tomography is essential for appropriate management and improved outcomes. These cases illustrate the variability in presentation and emphasize the importance of considering DDMS in the differential diagnosis of unilateral cerebral atrophy with neurological deficits.