Rationale:
Reports of imaging lesions in Dravet Syndrome due to SCN1A mutation are typically related to individual epilepsy surgical case series. In this abstract a case is described in which a frontal lobe neoplasm was discovered in an adolescent patient with SCN1a-related Dravet Syndrome.
Methods:
The patient is a male whose first seizure occurred at less than a year of age with fever. The patient developed hemiclonic seizures, myoclonic seizures, tonic-clonic seizures, and episodic status epilepticus. Sodium-channel blockers worsenedhis seizures prior to genetic diagnosis. MRI at one year of age was normal. At two years a de novo variant in SCN1A c.3995 G >A was discovered and he was given a diagnosis of Dravet Syndrome.
The patient continued to be treated medically with numerous treatments but neuroimaging was not repeated until late-school age when CT was performed due to a head injury. The CT scan showed no pathology.
Two years afterwards, the family became concerned about polypharmacy causing excessive drowsiness. No new focal deficits were noted. The patient was taking fenfluramine, cannabidiol, clobazam, and verapamil. Medication adjustment increased his seizures and worsened severity, but did not improve the drowsiness. Following a longer than typical seizure in school, emergency room evaluation repeated his CT scan, demonstrating a cystic lesion in the base of the right frontal lobe.
Since diagnosis, we performed video EEG to determine if his worsening may be related to lesional focal epilepsy. Video EEG demonstrated non-lateralizing generalized tonic-clonic seizures, and did not suggest specific involvement of the lesion. Serial imaging shows slow growth of the lesion. Biopsy has been performed.Results:
Focal lesions have been described in Dravet Syndrome. A summary of studies focusing on imaging features is provided in table 1. The reports demonstrate that focal lesions are rare. Until the recent reporting from Ventura et al, we are not aware of any patients being reported with neoplasms in Dravet Syndrome. Their three patients were adults at the time of reporting, but at the time of imaging for surgical evaluation, they would have been in their second or third decade. None responded to surgery.
Conclusions:
This case adds to the literature of Dravet Syndrome patients with neoplastic lesions. Cases to date have been adolescents or young adults, though they remain a rarity. Patients with unusual symptoms in adolescence may warrant an updated imaging study to assess for new lesions contributing to their condition.
Ventura R, Beltrán-Corbellini Á, Toledano R et al. Epileptogenic focal lesions in Dravet syndrome: A warning to investigators. Epileptic Disord. 2024; 26: 173–180.
Striano, P., Mancardi, M.M., Biancheri, R. et al Brain MRI Findings in Severe Myoclonic Epilepsy in Infancy and Genotype–Phenotype Correlations. Epilepsia 2007; 48: 1092-1096.
Barba C, Parrini E, Coras R et al. Co-occurring malformations of cortical development and SCN1A gene mutations. Epilepsia 2014;55(7):1009-19.
Funding: No funding was utilized in the generation of this report