Malformative lesions as well as neoplasms can cause intractable epilepsy in childhood. Even though the neoplastic nature of a lesion is evident in most cases, the distinction can be difficult in some patients. We present the case of a child with intractable epilepsy caused primarily by a glioneuronal malformation. Years after the first surgical intervention, a pleomorphic xanthoastrocytoma evolved from remnants of this lesion. This case suggests that glioneuronal malformations might be precursor lesions of pleomorphic xanthoastrocytomas.