18 F-SynVesT-1 PET 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 six months of convulsive seizures. Sustained seizure control was not achieved despite the use of multiple anti-epileptic agents. He had been plagued by unexplained paroxysmal bursts of laughter for more than 11 years. Video electroencephalography showed diffuse epileptic discharges prominent in the right hemisphere both in 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 in 18 F-FDG PET. The patient subsequently was enrolled in a clinical trial of 18 F-SynVesT-1 PET study in epilepsy, and an increased 18 F-SynVesT-1 uptake was noted in the mass. After excluding hormonal abnormalities, the patient underwent open resection of targeting HH. 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 for HHs.