Misleading features of neuroimaging and electroencephalography: insulinoma misdiagnosed as temporal lobe epilepsy

Epilepsy is a common disorder but diagnosis remains largely clinical. Although MRI and EEG significantly aid the diagnosis of epilepsy, these techniques may also be misleading and indicate abnormalities not related to phenomenology. Consequences of erroneous diagnosis of epilepsy may lead to aggressive and escalating pharmacotherapy with potentially serious side effects. Metabolic disorders, which may mimic epilepsy, should always be considered as they are potentially curable and may be fatal if untreated. We report a case of an insulinoma, misdiagnosed as temporal lobe epilepsy. We highlight the risks associated with misinterpretation of neuroimaging and EEG and outline an approach to differentiate between symptoms of insulinoma or neuroglycopenia and temporal epileptic seizures.