Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by vascular malformations involving brain, skin, and occasionally eyes. There is no recognized tumor predisposition in patients with SWS as there is with some other phakomatoses. We present a patient with SWS who developed a low-grade glioma (LGG). We hypothesize that there could be an association between SWS and LGG formation, noting that GNAQ mutations have been implicated in the underlying biology of both SWS and a subset of pediatric LGG. It is suggested that SWS may be a cancer predisposition syndrome.