Hypothalamic hamartomas--clinical, neuropathological and surgical aspects

Multimodal Approach for the Treatment of Complex Hypothalamic Hamartomas

Hypothalamic hamartomas (HHs) are rare congenital lesions formed by heterotopic neuronal and glial cells attached to the mammillary bodies, tuber cinereum, and hypothalamus.They often present with an intractable epilepsy typically characterized by gelastic seizures but commonly associated with other types of refractory seizures. The clinical course is progressive in most of the cases, starting with gelastic seizures in infancy and deteriorating into complex seizure disorders that result in catastrophic epilepsy associated with cognitive decline and behavioral disturbances.Hamartomas are known to be intrinsically epileptogenic and the site of origin for the gelastic seizures. As antiepileptic drugs are typically ineffective in controlling HH-related epilepsy, different surgical options have been proposed as a treatment to achieve seizure control. Resection or complete disconnection of the hamartoma from the mammillothalamic tract has proved to achieve a long-lasting control of the epileptic syndrome.Usually, symptoms and their severity are typically related to the size, localization, and type of attachment. Precocious puberty appears mostly in the pedunculated type, while epileptic syndrome and behavioral decline are frequently related to the sessile type. For this reason, different classifications of HHs have been developed based on their size, extension, and type of attachment to the hypothalamus.The bigger and more complex hypothalamic hamartomas typically present with severe refractory epilepsy, behavioral disturbances, and progressive cognitive decline posing a formidable challenge for the control of these symptoms.We present here our experience with the multimodal treatment for complex hypothalamic hamartomas. After an in-depth review of the literature, we systematize our approach for the different types of hypothalamic hamartomas.

Magnetic resonance-guided laser interstitial thermal therapy for drug-resistant epilepsy: A systematic review and individual participant data meta-analysis

Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has emerged as a popular minimally invasive alternative to open resective surgery for drug-resistant epilepsy (DRE). We sought to perform a systematic review and individual participant data meta-analysis to identify independent predictors of seizure outcome and complications following MRgLITT for DRE. Eleven databases were searched from January 1, 2010 to February 6, 2021 using the terms "MR-guided ablation therapy" and "epilepsy". Multivariable mixed-effects Cox and logistic regression identified predictors of time to seizure recurrence, seizure freedom, operative complications, and postoperative neurological deficits. From 8705 citations, 46 studies reporting on 450 MRgLITT DRE patients (mean age = 29.5 ± 18.1 years, 49.6% female) were included. Median postoperative seizure freedom and follow-up duration were 15.5 and 19.0 months, respectively. Overall, 240 (57.8%) of 415 patients (excluding palliative corpus callosotomy) were seizure-free at last follow-up. Generalized seizure semiology (hazard ratio [HR] = 1.78, p = .020) and nonlesional magnetic resonance imaging (MRI) findings (HR = 1.50, p = .032) independently predicted shorter time to seizure recurrence. Cerebral cavernous malformation (CCM; odds ratio [OR] = 7.97, p < .001) and mesial temporal sclerosis/atrophy (MTS/A; OR = 2.21, p = .011) were independently associated with greater odds of seizure freedom at last follow-up. Operative complications occurred in 28 (8.5%) of 330 patients and were independently associated with extratemporal ablations (OR = 5.40, p = .012) and nonlesional MRI studies (OR = 3.25, p = .017). Postoperative neurological deficits were observed in 53 (15.1%) of 352 patients and were independently predicted by hypothalamic hamartoma etiology (OR = 5.93, p = .006) and invasive electroencephalographic monitoring (OR = 4.83, p = .003). Overall, MRgLITT is particularly effective in treating patients with well-circumscribed lesional DRE, such as CCM and MTS/A, but less effective in nonlesional cases or lesional cases with a more diffuse epileptogenic network associated with generalized seizures. This study identifies independent predictors of seizure freedom and complications following MRgLITT that may help further guide patient selection.

The Mammillary Bodies: A Review of Causes of Injury in Infants and Children

Despite their small size, the mammillary bodies play an important role in supporting recollective memory. However, they have typically been overlooked when assessing neurologic conditions that present with memory impairment. While there is increasing evidence of mammillary body involvement in a wide range of neurologic disorders in adults, very little attention has been given to infants and children. Literature searches of PubMed and EMBASE were performed to identify articles that describe mammillary body pathology on brain MR imaging in children. Mammillary body pathology is present in the pediatric population in several conditions, indicated by signal change and/or atrophy on MR imaging. The main causes of mammillary body pathology are thiamine deficiency, hypoxia-ischemia, direct damage due to masses or hydrocephalus, or deafferentation resulting from pathology within the wider Papez circuit. Optimizing scanning protocols and assessing mammillary body status as a standard procedure are critical, given their role in memory processes.

Hamartoma of hypothalamus presented as precocious puberty and epilepsy in a 10-year-old girl

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Hamartoma of the hypothalamus may presents as central precocious puberty and gelastic epilepsy.

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It may be asymptomatic for long period.

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MRI is diagnostic in most of the cases.

Background

Hamartoma of the hypothalamus represents a well-known but rare cause of central precocious puberty and gelastic epilepsy. Due to the delicate site in which a tumor is located, surgery is often difficult and associated with considerable risks.

Case presentation

10-Year old girl presented with early and regular menstruation at the age of 1 year each cycle lasted for 3 days. She had developed breast, axillary and pubic hair at the age of five, and seven years respectively, with history of difficulty in speech especially articulation and epilepsy since childhood for which she is on medications. She had attacks of an inappropriate laugh. The laboratory tests were consisted with central precocious puberty, MRI shows suprasellar mass. She received leuprolide and antiepileptic medicines until surgery planned. Surgery was done with complete resection, with histopathology showing hypothalamic hamartoma. After surgery, there was complete remission of seizure.

She developed recurrence 4 years later and she is currently on anticonvulsant medications with few attacks of convulsions per week, and she has intellectual disabilities and low school performance.

Conclusion

The treatment of hypothalamic hamartoma associated with generalized epilepsy has been found to improve seizures and behavioral disturbances with an acceptable morbidity rate by using a variety of surgical approaches. Partial resection of a tumor may be sufficient to reduce seizure frequency and to improve behavior and quality of life with few side effects. Best outcomes are achieved when the patients are managed by an experienced multidisciplinary team and lifelong follow up is recommended.

Hypothalamic hamartomas: A comprehensive review of the literature - Part 1: Neurobiological features, clinical presentations and advancements in diagnostic tools

Hypothalamic hamartomas (HH) are rare, non-neoplastic heterotopic tissues which contains normal neurons and glia including oligodendrocytes and fibrillary astrocytes but in an abnormal distribution. They arise from the floor of the third ventricle, tuber cinereum, or mammillary bodies. Estimated incidence ranges from 1 in 50,000-1 in 1,000,000. Hypothalamic hamartomas are associated with different clinical presentations including various types of seizures, most characteristically; the gelastic seizures, precocious puberty, cognitive impairment, and behavioral changes. In this review, the authors discuss advancements in different diagnostic elements of hypothalamic hamartoma; including clinical features, EEG findings, and neuroimaging techniques. Moreover, different classifications described in the literature will be discussed.

Pallister-Hall Syndrome Presenting in Adolescence

Pallister-Hall syndrome (PHS) is an extremely rare syndrome of unknown prevalence with autosomal dominant inheritance due to GLI3 gene mutations classically characterized by the presence of a hypothalamic hamartoma and polydactyly. Additional diagnostic criteria include bifid epiglottis, imperforate anus, small nails, hypopituitarism, growth hormone deficiency, and genital hypoplasia. It is typically diagnosed in infancy and early childhood, presenting with seizures and/or precocious puberty due to the hypothalamic hamartoma, and with limb anomalies due to central polydactyly. Our patient had presented with polysyndactyly at birth. However, as this is not uncommon in infants and is usually as part of the sporadic, isolated form of polydactyly, no further work up was done. He then presented at age 16 years with a headache and subjective visual changes, with brain imaging revealing a hypothalamic hamartoma. He did not have a history of seizures or central precocious puberty. Genotyping revealed a pathogenic variant affecting the GLI3 gene. We encourage all clinicians to consider PHS or an associated syndrome with a clinical finding of polydactyly. Further, as the natural history continues to reveal itself, this patient's presentation provides important new data to the broad phenotypic spectrum of PHS.

Open resection of hypothalamic hamartomas for intractable epilepsy revisited, using intraoperative MRI

INTRODUCTION

Hypothalamic hamartomas (HHs) are rare non-neoplastic lesions which cause drug-resistant epilepsy with associated behavioural, psychiatric and endocrine issues. With the development of new minimally invasive techniques for the treatment of HH, there is a need to reappraise the effectiveness and safety of each approach. We review the outcomes of HH patients treated surgically, utilizing intraoperative magnetic resonance imaging (IOMRI), by a team of Alder Hey NHS Foundation Trust tumour and epilepsy neurosurgeons since 2011.

METHODS

Patient records of all HH cases operated on since 2011 were reviewed to confirm history of presentation and clinical outcomes.

RESULTS

Ten patients have undergone surgery for HH under the dual care of Alder Hey tumour and epilepsy neurosurgeons during this period. Eight cases had a midline transcallosal, interforniceal approach with the remaining 2 having a transcallosal, transforaminal approach. All patients had an IOMRI scan, with 40% needing further tumour resection post-IOMRI. Forty percent had a total resection, 3 patients had near-total resection and 3 patients had subtotal resection (~ 30% tumour residual on post-operative MRI). No new neurological complications developed post-operatively. Hypothalamic axis derangements were seen in 3 cases, including 1 diabetes insipidus with hypocortisolaemia, 1 hypodipsia and 1 transient hyperphagia. Eighty percent are seizure free; the remaining two patients have had significant improvements in seizure frequency.

CONCLUSIONS

IOMR was used to tailor the ideal tumour resection volume safely based on anatomy of the lesion, which combined with the open transcallosal, interforniceal route performed by surgeons experienced in the approach resulted in excellent, safe and effective seizure control.

A novel use of the NeuroBlate SideFire probe for minimally invasive disconnection of a hypothalamic hamartoma in a child with gelastic seizures

The authors describe the case of a 22-month-old boy who presented with gelastic seizures and developmental delay. Magnetic resonance imaging and video-electroencephalography monitoring revealed a primarily intraventricular hypothalamic hamartoma and gelastic seizures occurring 20-30 times daily. The patient was treated with various regimens of antiepileptic medications for 16 months, but the seizures remained medically intractable. At 3 years of age, he underwent stereotactic laser ablation with an aim of disconnection of the lesion. The procedure was performed with the NeuroBlate SideFire probe. To the authors' knowledge, this is the first reported use of this technology for this procedure and serves as proof of concept. There were no perioperative complications, and 2 years postprocedure, the patient remains seizure free with marked behavioral and cognitive improvements.

Management of Epilepsy Due to Hypothalamic Hamartomas

A hypothalamic hamartoma consists of hyperplastic heterotopic tissue growing in a disorganized fashion. These lesions occur in about one per 50,000 to 100,000 people. Hypothalamic hamartomas can cause intrinsic epileptogenesis leading to gelastic seizures. Surrounding cortical structures may also develop secondary epileptogenesis. Persistent seizures caused by hypothalamic hamartomas can be debilitating and result in significant cognitive and behavioral impairment. Early recognition and treatment is important in controlling seizures and in preventing further cognitive deterioration. Some patients experience improved cognition and behavior following early treatment, suggesting that hypothalamic hamartomas represent a reversible epileptic encephalopathy. The outcome of epilepsy associated with these lesions has significantly evolved with the availability of new treatment techniques and an improved understanding of its pathogenesis. Increasing evidence supporting the role of hypothalamic hamartomas as a cause of gelastic seizures and secondary epileptogenesis has led to more frequent use of surgery as the definitive treatment. Several minimally invasive procedures have been devised, including neuroendoscopic approaches and different stereotactic radio and laser ablation techniques. Each of these techniques can lead to unique adverse events. We review the various classification schemes used to characterize hypothalamic hamartomas and the recommended surgical approaches for each subtype. We also review the literature for currently available treatment modalities and compare their efficacy in controlling seizures and their safety profiles.

Pure endoscopic management of epileptogenic hypothalamic hamartomas

Hypothalamic hamartomas (HH) are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Their usual clinical presentation is characterized by gelastic/dacrystic seizures which often become pharmaco-resistant and progress to secondary focal/generalized intractable epilepsy causing mostly in children cognitive and behavioral problems (particularly in cases of progressive epileptic encephalopathy) and precocious puberty. Whereas gelastic seizures can be surgically controlled either by resection of the lesion or disconnection (tissue-destructive) procedures, aimed at functionally prevent the spreading of the epileptic burst; generalized seizures tend to respond better to HH excision rather than isolated neocortical resections, which generally fail to control them. Prospective analysis of 14 consecutive patients harboring HH treated in an 8-year period; 12 patients had unilateral and two bilateral HH. All patients were managed by pure endoscopic excision of the HH. The mean operative time was 48 min and mean hospital stay was 2 days; perioperative blood loss was negligible in all cases. Two patients showed a transient diabetes insipidus (DI); no transient or permanent postoperative neurological deficit or memory impairment was recorded. Complete HH excision was achieved in 10/14 patients. At a mean follow-up of 48 months, no wound infection, meningitis, postoperative hydrocephalus, and/or mortality were recorded in this series of patients. Eight patients became seizure free (Engel class I), 2 other experienced worthwhile improvement of disabling seizures (Engel class II); 2 patients were cured from gelastic attacks while still experiencing focal dyscognitive seizures; and 2, having bilateral HH (both undergoing unilateral HH excision), did not experience significant improvement and required later on a temporal lobectomy coupled to amygdalohyppocampectomy. Overall, the followings resulted to be predictive factors for better outcomes in terms of seizure control: (1) cases of unilateral, Delalande class B, HH, (2) shorter history of epilepsy. Endoscopic resection of HH proved, in our series, to be effective in achieving complete control or in reducing the frequency of seizures. Furthermore, this approach has confirmed its minimally invasive nature with a very low morbidity rate: of note, it allowed to better preserve short-term memory and hypothalamic function.

Sellar and Parasellar Imaging

The skull base is a complex anatomical region that harbors many important neurovascular structures in a relatively confined space. The pathology that can develop at this site is varied, and many disease processes may present with similar clinical and neuroimaging findings. While computed tomography maintains a role in the evaluation of many entities and can, for instance, delineate osseous erosion with great detail and characterize calcified tumor matrices, magnetic resonance imaging (MRI) is the mainstay in the neuroimaging assessment of most pathology occurring at the skull base. Various MRI sequences have proven to be robust tools for tissue characterization and can provide information on the presence of lipids, paramagnetic and diamagnetic elements, and tumor cellularity, among others. In addition, currently available MRI techniques are able to generate high spatial resolution images that allow visualization of cranial nerves and their involvement by adjacent pathology. The information obtained from such examinations may aid in the distinction of these disease processes and in the accurate delineation of their extent prior to biopsy or treatment planning.

The ventrolateral hypothalamic area and the parvafox nucleus: Role in the expression of (positive) emotions?

The lateral hypothalamus has been long suspected of triggering the expression of positive emotions, because stimulations of its tuberal portion provoke bursts of laughter. Electrophysiological studies in various species have indeed confirmed that the lateral hypothalamus contributes to reward mechanisms. However, only the rudiments of the neural circuit underlying the expression of positive emotions are known. The prefrontal cortex, the lateral hypothalamus, and the periaqueductal gray matter (PAG) are involved in these circuits; so, too, are the brainstem nuclei that control the laryngeal muscles and subserve mimicry, as well as the cardiovascular and respiratory systems. The implicated populations of hypothalamic neurons have not been defined either anatomically or molecularly. One promising candidate is the novel parvafox nucleus, which we recently described, in the murine medial forebrain bundle (mfb), which specifically expresses parvalbumin and Foxb1. With the molecularly defined parvafox nucleus as a centerpiece, the inputs from the prefrontal cortex and the projections to the PAG and brainstem can be studied with precision. By drawing on genetic approaches, it will be possible to manipulate the circuitry selectively with spatial and temporal exactitude and to evaluate the concomitant autonomic changes. These data will serve as a basis for imaging studies in humans using various paradigms to provoke the expression of positive emotions. In conclusion, studies of the hypothalamic parvafox nucleus will reveal whether this entity represents the fulcrum for positive emotions, as is the amygdala for fear and the insula for disgust.

Hypothalamic hamartomas. Part 1. Clinical, neuroimaging, and neurophysiological characteristics

Hypothalamic hamartomas are uncommon but well-recognized developmental malformations that are classically associated with gelastic seizures and other refractory seizure types. The clinical course is often progressive and, in addition to the catastrophic epileptic syndrome, patients commonly exhibit debilitating cognitive, behavioral, and psychiatric disturbances. Over the past decade, investigators have gained considerable knowledge into the pathobiological and neurophysiological properties of these rare lesions. In this review, the authors examine the causes and molecular biology of hypothalamic hamartomas as well as the principal clinical features, neuroimaging findings, and electrophysiological characteristics. The diverse surgical modalities and strategies used to manage these difficult lesions are outlined in the second article of this 2-part review.

Gelastic seizures due to hypothalamic hamartoma: rapid resolution after endoscopic tumor disconnection

Gelastic epilepsy are focal seizures manifesting as recurrent brief seizures starting as laughter or grimaces. They are most commonly associated with other types of seizures and can be secondary to infectious, malformative, metabolic, or neoplastic processes involving the central nervous system. We report on an 18-month-old girl who presented since the age of 2 months with multiple, recurrent, unprovoked episodes of stereotypical laughter. Brain magnetic resonance study revealed an hypothalamic hamartoma. Endoscopic tumor disconnection of the hamartoma resulted in rapid resolution of neurological symptomatology.

The gelastic seizures-hypothalamic hamartoma syndrome: facts, hypotheses, and perspectives

Hypothalamic hamartoma (HH) can be associated with a wide spectrum of epileptic conditions, ranging from a mild form with seizures characterized by urge to laugh and no cognitive involvement up to a catastrophic encephalopathy with early onset gelastic seizures (GS), precocious puberty, and mental retardation. Moreover, a refractory, either focal or generalized, epilepsy develops during the clinical course in nearly all the cases. Neurophysiologic and neuroimaging studies have demonstrated that HH itself generates GS and starts a process of secondary epileptogenesis responsible for refractory focal or generalized epilepsy. The intrinsic epileptogenicity of HH may be explained by the neurophysiological properties of small GABAergic, spontaneously firing HH neurons. Surgical ablation of HH can reverse epilepsy and encephalopathy. Gamma-knife radiosurgery and image-guided robotic radiosurgery seem to be useful and safe approaches for treatment, in particular of small HH. Here, we review this topic, based on literature reports and our personal observations. In addition, we discuss pathogenetic hypotheses and suggest new approaches to this intriguing issue.

Suprasellar hamartoma and arachnoid cyst

OBJECTIVE

The differential diagnosis for suprasellar masses includes a variety of pathologies, ranging from stable and benign lesions to aggressive and malignant ones. We report a case of a suprasellar hamartoma associated with an arachnoid cyst and review the literature surrounding the topic.

CASE DESCRIPTION

A 32-year-old man who presented with headaches and nonspecific vision loss was found to have a cystic, calcified, and minimally contrast enhancing lesion of the suprasellar region. Intraoperative inspection revealed a discrete mass in the right side of suprasellar region that resembled normal brain completely enveloped by the basal arachnoid membranes including the membrane of Lillequist and was not connected to the brain. Fenestration and exploration of the cystic portion demonstrated a simple arachnoid cyst filled with what appeared to be cerebrospinal fluid. Given the adherence of the lesion to numerous perforating arteries arising from the posterior communicating artery, a biopsy with intraoperative confirmation was taken. Pathology was consistent with neuroglial tissue without evidence of neoplasia.

CONCLUSIONS

To our knowledge this is only the third case of an isolated suprasellar hamartoma described in the literature and the first of its kind to be associated with an arachnoid cyst.

Rare suprasellar glioblastoma: report of two cases and review of the literature

BACKGROUND AND IMPORTANCE

The suprasellar and hypothalamic/chiasmatic regions can harbor a broad range of pathologic conditions, both neoplastic and nonneoplastic; however, malignant gliomas are extremely rare in those regions.

CLINICAL PRESENTATIONS

Patient 1 was a 70 year-old man with weight loss and rapidly progressive visual impairment. A mass centered in the hypothalamus was detected on magnetic resonance (MR) imaging. The second patient, a 45 year-old woman, complained of visual symptoms and headaches. MR imaging revealed a combined intra- and suprasellar mass. In both instances, the preoperative differential diagnosis favored craniopharyngioma. Histological examination confirmed the diagnosis of glioblastoma.

CONCLUSION

We report two rare adult cases of hypothalamic/chiasmatic glioblastoma. The authors review the literature, highlighting the importance of considering this rare entity in the differential diagnosis of suprasellar and hypothalamic lesions.

Pediatric sellar and suprasellar lesions

Masses arising in the sella turcica and the suprasellar region are common in children. The type and frequency of the various lesions encountered in childhood differ from the adult presentation. This article reviews the embryology of the pituitary gland and its normal appearance in childhood as well as the imaging and clinical findings of the common and some of the uncommon lesions arising in the sella turcica, the pituitary stalk, the suprasellar cistern and the lower third ventricle in the pediatric population.

Two cases of precocious puberty associated with hypothalamic hamartoma

Hypothalamic hamartoma (HH) is a congenital malformation diagnosed based on magnetic resonance imaging (MRI) and histological findings; it is often associated with central precocious puberty (CPP), gelastic seizures, abnormal behavior and mental retardation. In the present paper, we report our retrospective hypothesis that there is a relationship between symptoms and therapy, as well as the treatment for HH, and describe two cases of HH associated with CPP. Both cases had sessile masses located in the interpeduncular cistern, with extension to the hypothalamus on MRI (1.2 × 1.5 cm and 2.0 × 2.5 cm, respectively). The first case had intractable seizures, while the second had no seizures with paroxysmal discharge. In both patients, the hamartomas were partially removed, by γ-knife and surgical operation in the first case and surgically in the second, and a gonadotropin releasing hormone (GnRH) analogue was prescribed. One case showed improvement of both intelligence quotient (IQ) score and seizures, and the other showed improvements in IQ and abnormal behavior. It was difficult to determine any topology/symptom relationships. Surgery and GnRH analogue treatment can alleviate seizures, abnormal behavior and mental retardation associated with HH.

A review on the management of epilepsy associated with hypothalamic hamartomas

INTRODUCTION

Hypothalamic hamartomas are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Patients may be asymptomatic, but the usual presentation is gelastic seizures, precocious puberty, and/or developmental delay.

CLINICAL PRESENTATION

Without surgical intervention, the gelastic seizures, which are typically present in childhood, may progress to other seizure types, including generalized epilepsy, and are generally refractory to antiepileptic drugs.

SUMMARY

This review will discuss the clinical and electrophysiologic aspects of these lesions, as well as treatment options, including surgery, endoscopy, and radiosurgery.

Gelastic seizures associated with hypothalamic hamartomas. An update in the clinical presentation, diagnosis and treatment

Gelastic seizures are epileptic events characterized by bouts of laughter. Laughter-like vocalization is usually combined with facial contraction in the form of a smile. Autonomic features such as flushing, tachycardia, and altered respiration are widely recognized. Conscious state may not be impaired, although this is often difficult to asses particularly in young children. Gelastic seizures have been associated classically to hypothalamic hamartomas, although different extrahypothalamic localizations have been described. Hypothalamic hamartomas are rare congenital lesions presenting with the classic triad of gelastic epilepsy, precocious puberty and developmental delay. The clinical course of patients with gelastic seizures associated with hypothalamic hamartomas is progressive, commencing with gelastic seizures in infancy, deteriorating into more complex seizure disorder resulting in intractable epilepsy. Electrophysiological, radiological, and pathophysiological studies have confirmed the intrinsic epileptogenicity of the hypothalamic hamartoma. Currently the most effective surgical approach is the trancallosal anterior interforniceal approach, however newer approaches including the endoscopic and other treatment such as radiosurgery and gamma knife have been used with success. This review focuses on the syndrome of gelastic seizures associated with hypothalamic hamartomas, but it also reviews other concepts such as status gelasticus and some aspects of gelastic seizures in other locations.

Gamma knife surgery for epilepsy related to hypothalamic hamartomas

Numerous neurosurgical approaches are available for children presenting with hypothalamic hamartomas (HHs) associated with severe epilepsy. A concern regarding the impairment of short-term memory after resective surgery is promoting the exploration of less invasive alternatives like radiosurgery. Gamma knife radiosurgery (GKS) can lead to a real reversal of the epileptic encephalopathy. Three years after radiosurgery, 60% of the children have an excellent result with complete seizure cessation in 40% and rare nondisabling seizures in 20%, often in association with dramatic behavioral and cognitive improvement. No permanent neurologic complications have thus far been reported. Rare transient cases of poikilothermia have been observed. GKS is clearly the safer approach for these difficult patients. Young patients with severe epilepsy and neurocognitive comorbidity must be treated by using a curative approach as early as possible. Topological type (according to our original classification) is the major feature for selection of the best treatment strategy. Type I HH deeply embedded in the hypothalamus is treated safely and efficiently by GKS. Type II HH can be resected by either endoscopic or transcallosal approaches or treated by GKS depending on the parent's choice and severity of epilepsy. In small type III HH, GKS is the safer procedure because of the very close relationship to the fornix and mammillary bodies. Types V (rarely epileptic) and IV are frequently operable by disconnection. Very large type VI (or mixed type) with a large component above the floor of the third ventricle must be disconnected, and then the upper remnant is best treated by GKS using a staged technique. Overall, when the lesion is sufficiently small, GKS offers a rate of seizure control comparable to microsurgery but with much lower risk. The disadvantage of radiosurgery is its delayed action. Longer follow-up is mandatory for a reliable evaluation of the role of GKS.