Polymicrogyria is a malformation of cortical organisation morphologically marked by an irregular brain surface with multiple excessively folded small gyri. Cortical thickness is reduced but appears increased in some areas as a result of the fusion of small gyri.1 On magnetic resonance imaging (MRI) polymicrogyria is delineated by an abnormal gyral pattern, increased cortical thickness and irregularity of the cortical–white matter junction.2

Clinical presentation largely depends on the localisation of polymicrogyria and the extent of cortical involvement. Several topographically distinct syndromes of bilateral polymicrogyria have been described.2 Polymicrogyria may be the result of acquired intrauterine insults (ischaemia, twinning, infections with cytomegalovirus, toxoplasma, varicella-zoster virus) as well as inherited (familial polymicrogyria syndromes) or metabolic disorders (Leigh syndrome, Zellweger syndrome).1

A 26-year-old right-handed man was referred to the video-electroencephalographic monitoring unit for presurgical evaluation of medically intractable epilepsy. The patient was born after an uneventful pregnancy and delivery. His developmental milestones were age relevant and he attended a regular school. His epilepsy manifested at the age of 17 years with epigastric auras, reaching a maximum frequency of several auras per week. One year later the epigastric auras were followed by secondary generalised tonic–clonic seizures with a marked postictal confusion. Routine electroencephalography (EEG) …