18 F-SynVesT-1 positron emission tomography in a hypothalamic hamartoma with abnormal uptake.

Hypothalamic hamartomas (HHs) are uncommon benign lesions of neuronal and glial cells in the inferior hypothalamus. They have been linked to epilepsy, premature puberty, and cognitive and behavioral impairment. We report a 13-year-old patient who was referred to a multidisciplinary treatment team for epilepsy with 6 months of convulsive seizures. Sustained seizure control was not achieved despite the use of multiple antiepileptic agents. He had been plagued by unexplained paroxysmal bursts of laughter for >11 years. Video-electroencephalography showed diffuse epileptic discharges prominent in the right hemisphere in both interictal and ictal phases. Magnetic resonance imaging demonstrated an isointense gray matter mass on the right lateral walls of the third ventricle, with focal hypometabolism on 18 F-fluorodeoxyglucose positron emission tomography (PET). The patient subsequently was enrolled in a clinical trial of 18 F-SynVesT-1 PET in epilepsy, and an increased 18 F-SynVesT-1 uptake was noted in the mass. After excluding hormonal abnormalities, the patient underwent open resection targeting HHs. We used 18 F-SynVesT-1 as a specific PET tracer for synaptic vesicle glycoprotein 2A, which is ubiquitously expressed in brain synapses. 18 F-SynVesT-1 PET may hold promise as a supplementary tool in the presurgical localization and evaluation of HHs.