Seizure 1998; 7:167-171 CASE REPORT Hypothalamic hamartomas causing gelastic epilepsy: Two cases and a review of the literature N. GEORGAKOULIAS*, C. VIZE*, A. JENKINS* & E. SINGOUNAS t * Department of Neurosurgery, Newcastle General Hospital, UK; t Evangelismos General Hospital, Athens, Greece Correspondence to: N. Georgakoulias, Department of Neurosurgery, Middlesbrough General Hospital, Ayresome Green Lane, Middlesbrough, Cleveland, TS5 5AZ, UK Two cases of hypothalamic hamartomas causing gelastic epilepsy are described. The clinical presentations and the radiological features are presented, and the mechanisms involved in laughing attacks are discussed. The literature is reviewed and it is suggested the complete extirpation of the hamartomas is the treatment of choice in gelastic epilepsy. Key words: hypothalamic hamartomas; gelastic epilepsy. INTRODUCTION improvement. One month later, he was admitted fol- lowing a generalized seizure and vigabritin 500 mg Gelastic epilepsy, or laughter attacks (Greek gelos = bd was added. laugh), may occur in association with hypothalamic Unfortunately his fits continued to increase until hamartomas. The management of affected patients is he was having between 10 and 20 seizures per day. difficult and controversial. In this report we present These were sometimes spontaneous but oftenprecipi- two patients to illustrate dilemmas in management, tated by laughing and consisted of a short period of and have reviewed the literature associated with this laughter followed by hand-clapping and various au- condition. tomatisms. On one occasion he put his shoes into the washing machine. He had loss of awareness of his surroundings and amnesia for the event, CASE1 A magnetic resonance imager (MR/) scan showed on T l-weighted images an isodense nonenhancing pe- This patient, an 8-year-old boy, presented to the pae- dunculated mass within the interpenduncular cistern diatric neurology department after his teacher and measuring 2.5 cm in diameter, with apparent com- classmates had reported to his parents that he had pression of the hypothalamus. T2-weighted images recently developed a tendency to prolonged spells of revealed increased signal intensity. This was thought inappropriate giggling. This was followed by several to be a hamartoma of the tuber cinereum. In view of minutes where he had a glazed expression and ap- the failure of his seizures to respond to medication, it peared distant. There were no obvious precipitating was decided to admit him for assessment and surgery. factors. By the time of his admission he was still tall for his Examination showed him to be tall for his age but age (10 years) at the 98th centile and had evidence of normal intelligence and with no neurological fea- of development of secondary sexual characteristics. tures. An EEG showed an ill-defined right-sided ab- At craniotomy a firm mass was found and was normality and a CT scan was reported as normal. approached between the optic nerve and the carotid He was started on carbamazepine but showed little artery on the right. Unfortunately it was only possible 1059-1311/98/020167+ 05 $12.00/0 (~ 1998 British EpilepsyAssociation 168 N. Georgakoulias et al to remove a portion of the mass. Histology showed pattern which is thought to be unique to humans I. mature brain tissue composed of neuropil, neurons or Pathological laughter is inappropriate, uncontrol- variable morphology, nests of small and differentiated lable, often prolonged, and cannot be inhibited volun- cells, and aggregates of neurones resembling basal tarily. It can be elicited by trivial, non-specific stimuli. forebrain, islands of Caleja and myelinated tracts. This has been observed in pseudobulbar and bulbar Postoperatively his fits were unchanged. He de- syndromes with a vascular, inflammatory, toxic or de- veloped diabetes insipidus but responded well to generative aetiology. It is probably due to a disorder Desamino-D-arginine-Vasopressin (DDAVP) treat- of motor expression of emotion rather than of emo- ment. tion itself. There is no associated EEG abnormality. This is distinct from the laughter of gelastic epilepsy where the duration of laughter is usually short (less CASE2 than 30 seconds), although when associated with a complex partial seizure it may be more prolonged. This 38-year-old lady had had epilepsy since the age For a seizure to be considered gelastic, laughter has of 2. She had a normal birth history and no febrile to be inappropriate, stereotyped, and not precipitated convulsions. Her seizures had always been badly con- by either specific (joke-humour) or non-specific stim- trolled, but 3 years before admission deteriorated to a ulus. level where she was having five or six major seizures Gaskon and Lomboso (2) proposed the following a month with frequent minor seizures. By the time criteria for the diagnosis of gelastic epilepsy: of her admission to hospital she had been on carba- I stereotyped recurrence; mazepine and valproate up to the maximum tolerated dose. Vigabatrin, after an initial response, has resulted 2 absence of external precipitants; in worsening of seizures; lamotrigine and gabapentin 3 EEG abnormality, ictal or interictal; had been poorly tolerated. While on the wards he had several seizures and these were observed to be 4 absence of other causes of pathological laughter; preceded by attacks of uncontrollable laughter. This feature had not been mentioned by her or her husband 5 concomitant fits of other types are frequent. at previous interviews. Gelastic seizures can be isolated, or may be part of An electroencephalogram (EEG) showed occa- a complex partial seizure with loss of memory, au- sional runs of right temporal slow-wave activity but tomatism, and motor symptoms as in the two cases no definite focus. A MRI scan showed some gen- reported here. They are frequently associated with eralized atrophy, particularly of the posterior fossa hypothalamic masses which are usually hamartomas: structures, and a well-defined right-sided mass in the more than 45 cases with gelastic epilepsy 3 have been region of the tuber cinereum. reported in the literature up to 1988. At surgery via a pterional craniotomy the lesion Of 50 histologically verified cases from another re- was approached anterior and posterior to the carotid port, 74% were associated with precocious puberty artery. A subtotal excision was made. Histology and 48% with gelastic seizures, generalized seizure showed dense gliosis with an abnormal pattern of and behavioural disturbances. oligodendroglial cells and neurons. It was felt to be Ictal laughter may be rarely a component of com- consistent with a hypothalamic hamartoma. plex partial seizures of temporal or frontal origin, or Postoperatively the patient remained seizure-free at infantile spasms. l-year follow up. Most patients with gelastic seizures associated with hamartomas have an early onset of seizure activity and a variety of behavioural or psychiatric disor- DISCUSSION ders. Most have a progressive reduction of intellectual functions. Laughter, the somatic expression of mirth, involves movements of facial muscles and is associated with clonic contractions of the thoracic cage and abdomi- Hypothalamic hamartomas nal wall. Neurologically, this involves the limbic sys- tem, especially the anterior cingulate gyms, and the These are well-defined masses of mature ganglionic brain stem I. Mirth, the emotional accompaniment of tissue which are usually attached to the tuber laughter, involved the basal temporal cortex, particu- cinereum or the mamilliary bodies 5. larly the fusiform and parahippocampal gyri. The two They may be sessile to pedunculated, usually ex- systems interrelate with each other and with other cor- tending into the interpeduncular cistern but some- tical and subcortical regions, to produce a behaviour times into the floor of the third ventricle. Hypothalamic hamartomas causing gelastic epilepsy 169 (a) (b) / i" ~o (c) Fig. 1: a--c. Axial, sagittal and coronal MRI studies of Case 1 showing large midline hypothalamic mass. Valdueza et al 6 have shown that the pendunculated be confused with other lesions in the same area, such hamartomas are more commonly associated with pre- as craniopharyngioma, low-grade hypothalamic astro- cocious puberty, whereas the sessile hamartomas are cytoma, ganglioglioma, optic pathway glioma, lym- more commonly associated with gelastic seizures. phoma, or suprasellar germinoma 12. This is in accordance with clinical and radiological The presence of active neural tracts connecting a findings regarding our patients. hamax~toma and number of hypothalamic nuclei and They consist of grey and white matter of varying providing a potential excitatory pathway may explain degrees of differentiation, and indeed in some cases the presence of precocious puberty in many of these nerve fibres have been traced from the hamartoma patients. into the tuberal region of the hypothalamus. They The pathogenesis of precocious puberty is not clear. are often associated with cerebral or extracerebral It has been speculated that local pressure, abnormal congenital abnormalities, including microgyria, het- neural connects, endocrine activity or a combination erotopia, cysts, callosal defects, polydactyly, facial of these may play a part. Gullet et a112 reported a pa- anomalies and heart defects7-1°. tient with hypothalamic hamartoma and precocious The investigation of choice is MRI. On T1 images puberty who showed normal pituitary function apart hamartomas appear as nonenhancing, isointense