Abstracts

Focal transmantle dysplasia (FTD) is a specific malformation of cortical development (MCD) with abnormality extending from the wall of lateral ventricle to the cortical surface. FTD varies from a linear band to an entirely malformed lobe and probably associated with maldifferentiation of the stem cells generated in the germinal zone. FTD was first described in 1997 and seen in 4% of MCDs in childhood. FTD usually occurs as an isolated finding although has rarely been reported in neurofibromatosis type 1 and tuberous sclerosis complex. There has been no report of FTD caused by prenatal vascular insult (PVI)., We retrospectively reviewed the clinical, EEG, and neuroimages of 3 patients with FTD caused by PVI, 2 from intraventricular hemorrhage (IVH) and 1 from cerebral ischemia. 1 patient underwent epilepsy surgery., Patient 1 is a 6-year-old-left-handed-twin B girl who was born at 28 weeks GA with IVH grade 4 and required ventilator supports for 3 months. She had multiple types of seizures including myoclonic, secondarily generalized tonic-clonic, absence, and asymmetric tonic seizures. Four MRI scans were interpreted as ischemic injury in the left frontal region. FTD was diagnosed during presurgical evaluation. EEG showed epileptic focus in the left frontal and frontal vertex regions. Ictal SPECT showed left mesial frontal hyperperfusion. Resection of FTD and epileptogenic zone after subdural EEG implantation led to seizure free. Pathology revealed focal cortical dysplasia.
Patient 2 is a 23-month-old-left handed girl who was born at 24 weeks GA. She had fetal distress due to abruption placenta with subsequent global developmental delay (GDD) and one seizure described as right-sided clonic jerks at age 23 months . MRI was interpreted as periventricular nodular heterotopias but apparently it was FTD in the left frontal region. Her seizure has been well controlled with oxcarbazepine.
Patient 3 is a 14-year-old-right-handed girl who was born at 36 weeks GA to a mother who had severe hyperemesis requiring total parenteral nutrition at 15 weeks GA. The patient had GDD, ADHD, severe left hemiparesis, and focal epilepsy. MRI showed extensive polymicrogyria in the right fronto-centro-temporal and FTD in the right frontal region. She was found having electrical status epilepticus during slow sleep (ESES). Her cognition improves dramatically with diazepam., Our report suggests that PVI, either ischemia or hemorrhage, can cause FTD. FTD is probably underrecognizable as it is a relatively new type of MCD and can have varieties of clinical courses. This report may help neurologists to expand the scope and better understand the pathophysiology of FTD and to be more aware of this condition. Adequate treatment of PVI may prevent the development of FTD.,