Archives of Disease in Childhood 1995; 72: 443-444 Laughing seizures due to a midline intraventricular neoplasm in tuberous sclerosis Saman Gunatilake, D G Harendra De Silva Abstract Laughing seizures have been described in association with hypothalamic hamar- tomas and precocious puberty. Laughing seizures due to a neoplasm arising from the floor of the left lateral ventricle extending down towards the hypo- thalamus in a child with tuberous sclerosis is reported. This combination has not been reported before and empha- sises the importance of imaging to diag- nose such midline lesions in children with paroxysmal laughing. (Arch Dis Child 1995; 72: 443-444) Keywords: tuberous sclerosis, gelastic seizures, hypothalamic neoplasms. General Hospital, Galle, Sri Lanka S Gunatilake Department of Paediatrics, University of Ruhuna, Galle, Sri Lanka D G H De Silva Correspondence to: Dr Saman Gunatilake, 43 Fife Road, Colombo-5, Sri Lanka. Accepted 23 January 1995 Laughing seizures may be idiopathic or may be associated with intracranial mass lesions in the region of the hypothalamus, limbic system, or the temporal lobe. These seizures are also known as gelastic seizures and consist of stereotyped attacks of laughter varying from grinning, giggling, to joyful weeping. Laughing seizures due to hypothalamic neoplasms have been reported before. We report a case of laughing seizures in a child with tuberous scle- rosis due to a neoplasm arising from the floor of the left lateral ventricle extending down towards the hypothalamic region. This combi- nation has not been reported before. Case report This boy first developed seizures at the age of 8 months. These seizures consisted of tonic, clonic movements of either upper limb g _~~~~~~~~~~~~~M - 7s! w i Figure 1 (A) Rounded enhancing neoplasm arising close to the left foramen of Monro. (B) Subependymal calcified glial nodules. lasting for about a minute and the child was unconscious. These seizures occurred at the rate of one to two a week and the response to treatment was poor. Neurologically the child did not have any abnormality at that time and his motor and mental development were normal. Though he continued to have seizures, the child developed normally and at the age of 5 years he started having episodes of inappro- priate laughter. These occurred almost daily, mostly in the mornings. He had warning of the impending seizure and clung to his mother and then started laughing. He also had involuntary movements of the right arm during the seizure. He is now 7 years old and attends a normal school. Physical and mental development was normal and his intelligence is comparable with other normal children of his age. He is an only child from a non-consanguineous marriage. The parents do not have any features of tuberous sclerosis. There were three white skin macules measuring about 1 to 2 inches on his trunk and limbs. He had no facial angio- fibromas. There were no other skin lesions, and he had no papilloedema or retinal lesions. Electroencephalography showed paroxysmal high amplitude polyspike and wave complexes in all areas. Computed tomography showed a rounded, well circumscribed enhancing neo- plasm arising from the floor of the left lateral ventricle close to the foramen of Monro and extending downwards into the hypothalamic region (fig IA) and subependymal calcified glial nodules (fig 1B). Ventricular dilation was noted on the left side, a result of the tumour causing obstruction to the foramen of Monro. Magnetic resonance imaging in addition to showing the neoplasm revealed the presence of multiple cortical and subcortical tubers (fig 2A, B). Discussion The association of gelastic seizures with hypo- thalamic neoplasms is now well recognised and is considered a specific epileptic syn- drome.' Precocious puberty is an associated feature in most cases and may follow gelastic seizures.2 This association has led to the suggestion that a centre for laughter exists in the region of the hypothalamus. Differen- tiating gelastic seizures from psychiatric disease or behavioural abnormalities may be difficult. Our patient illustrates some of the differentiating features that favour the diag- nosis of seizures. The seizure episodes were sudden in onset, brief, stereotyped, and occurred in a child without any history of psy- chiatric or behavioural problem. Often the laughter in a gelastic seizure is of a different 443 group.bmj.com on October 18, 2011 - Published by adc.bmj.com Downloaded from