Hypothalamic hamartomas and Gelastic seizures. Chilean experience in a pediatric epilepsy surgery program during 13 years - Review of the literature

Abstract

Background: Hypothalamic Hamartomas (HH) are benign tumors with hyperplastic heterotopic tissue growing in a disorganized fashion. They are associated with refractory epilepsy. The typical seizure type is "Gelastic". HH can produce different types of seizures. The epileptogenesis has been discussed focusing in "hamartomacentrism" and "extra hamartoma epileptogenesis".Objectives: To determine the pre-surgical aspects and surgical techniques with the best outcomes in HH associated to refractory epilepsy. Methods:We studied pediatric patients with HH who underwent epilepsy surgery between 2004 and 2017. We analyzed the type of seizures, neurological comorbidity, type of hamartoma in MRI, the electroencephalography records, type of surgery and outcome according to the Engel's and ILAE's classification. We also compare the neuropsychological evaluation before and after surgery.Results: 7 cases fulfilled inclusion criteria, the ages of starting symptoms vary since 4 months to 7 years old; the mean time of surgery was 5 years. 14% of cases had Gelastic semiology as the first seizure, 57% experienced gelastic seizures and 85% of the cases had at least one generalized seizure. 71.4% were classified as wide implantation and 28.6% as pedunculated. 100% underwent open surgery, through trans-callosal technique in 42.85% and 57.14% through trans-silvian surgery. The outcome after surgery, according to Engle classification: 2/7 (28.57%) resulted with Ia; 2/7 (28.57%) were Ic; 1/7 (14.28%) was type II, 1/7 (14.28%) was type III and 1/7 (14.28%) was type IVc. Conclusions:The possibility to remove the totality of the tumor was 14%. Nonetheless the results evaluated with ILAE's and Engel's outcome score were not bad, possibly because the surgery gets the splitting of the hamartoma from the hypothalamus. The 84% are classified with improvement after surgery and 42.85% are currently without seizures. No patient was able to discontinue the AEDs; 57% required increase the doses and the number of medications.