Selective surgical mamillo-thalamic tract disconnection in hypothalamic hamartoma results in complete disappearance of gelastic seizures.

Hypothalamic hamartoma is a less common condition characterized by the several types of epileptic seizures including the gelastic type. It is reported that gelastic seizures are resistant to medical treatment with anticonvulsants, while stereotactic thermocoagulation or Gamma Knife radiosurgery are effective for seizure control. Here, we report an individual case where direct surgical resection disconnecting hypothalamic hamartoma from mammillothalamic tract resulted in complete disappearance of gelastic seizures without deterioration of cognitive function. A 6-year-old boy developed gelastic seizures at the age of 2 and suffered from precocious puberty. Anticonvulsants including carbamazepine and zonisamide failed to control seizures. The patient underwent direct division of the mammillothalmic tract by removal of hypothalamic hamartoma partially via anterior interhemispheric approach. It was observed that gelastic seizures disappeared completely after the surgical treatment without any endocrine and cognitive dysfunction for a follow-up period of 14 years. The mammillothalamic tract which connects anterior nucleus of thalamus and mammillary bodies plays a key role in gelastic seizures related to hypothalamic hamartoma. In this case, we disconnected the hamartoma specifically from the mammillary bodies and not from the rest of hypothalamus. Effectively, it enabled permanent control of seizures. This result shows that fibers connecting other hypothalamic structures and the dorsomedial nucleus of thalamus are not involved in gelastic seizure propagation from the hypothalamic hamartoma. When surgical treatment of hypothalamic hamartomas is performed it has high morbidity associated with hypothalamic disorders. Therefore, disconnection between hypothalamic hamartoma and mammillary bodies presents a possibility of reducing hypothalamic damage. Surgical disconnection between hamartoma and mammillothalamic tract carries minimal hypothalamic injury risk and our results suggest that it has the potential of seizure control for intractable gelastic seizures with less complications.

Pediatric Optic Pathway/Hypothalamic Glioma.

Optic pathway/hypothalamic gliomas (OP/HGs) are rare astrocytic tumors that appear more commonly among young children and often are unresectable. They comprise approximately 2% of all central nervous system tumors and account for 3-5% of pediatric intracranial tumors. Initial manifestations are often visual disturbances, endocrinopathies and hypothalamic dysfunction such as the diencephalic syndrome, and sometimes hydrocephalus due to cerebrospinal fluid (CSF) outflow obstruction. In many cases, the tumors are diagnosed late in the clinical course because they silently enlarge. These tumors consist mostly of histologically benign, World Health Organization (WHO) grade I tumors represented by pilocytic astrocytomas (PA), the rest being pilomyxoid astrocytomas (PXA) - WHO grade II tumors. In young pediatric patients, however, can be seen PXA that show aggressive clinical course such as CSF dissemination. Our small series of 14 non-Neurofibromatosis type 1 (NF-1) OP/HGs PA patients underwent extended resection without any adjuvant treatments. The median age at initial treatment was 11.5 ± 6.90 years (range, 1-25 years) and median follow up 85.5 ± 25.0 months. Surgical resection for OP/HGs results in acceptable middle-term survival, tumor control and functional outcome equivalent to chemotherapy. There is, however, no longer doubt that chemotherapy with or without biopsy and as-needed debulking surgery remains the golden standard in management of OP/H. Clinical conditions and treatment plans for OP/HGs vary depending on their structure of origin.