Background Sturge-Weber syndrome (SWS) is an uncommon etiology of hemiplegic migraine-like (HM-like) attacks, associated with epilepsy and mental retardation. Case We report the case of a 40-year-old woman with SWS who has been suffering from HM-like episodes since she was 24, with no history of seizure or mental retardation. Susceptibility weighted imaging (SWI)-MRI and CT scans have shown bilateral calcifications of the choroidal plexuses, a developmental venous anomaly with dilated transmedullary veins and a left parieto-occipital leptomeningeal angioma. 18F-Fluorodeoxyglucose (FDG)-PET/CT revealed a diffuse left-hemisphere hypometabolism. The comparison between the MRI performed at the age of 24 and the one performed at the age of 40 highlighted a progressive unilateral fronto-temporo-parietal atrophy. Surprisingly, even now, cognitive functions of this patient are relatively preserved. Lamotrigine permitted an improvement of HM-like attacks. Discussion Explanations for this minimally symptomatic form of SWS may be the absence of seizure, the importance of her deep venous drainage, the absence of cortical calcification and white matter impairment in the affected hemisphere, and, paradoxically, the severely asymmetric cortical metabolism. Furthermore, this case reinforces the hypothesis that alteration of cerebral hemodynamics could precipitate the cortical spreading depression giving rise to migraine with aura. Conclusion We propose to consider SWS as a cause of apparently isolated hemiplegic migraine and lamotrigine as a preventive medication in HM-like attacks.