Abstracts

Outcome after epilepsy surgery with histopathology correlations indicated that different pathological findings of focal cortical dysplasia (FCD) had different outcome. FCD and balloon cells demonstrated best outcome with 75% seizure-free at least 1-year follow-up. Our objective is to correlate seizure outcome after surgery for FCD with pathological findings and variables associated with seizures outcome. We retrospectively reviewed patients who underwent surgery for drug-resistant partial epilepsy due to FCD and confirmed by histopathologic analysis between 1990-2002 with a minimum of 1-year follow-up. Histological findings were classified as: type Ia, architectural abnormalities, type Ib, architectural abnormalities plus giant or immature neurons, type IIa, architectural abnormalities plus dysmorphic neurons, and type IIb, architectural abnormalities plus dysmorphic neurons plus balloon cells. Seizure outcome was classified according to Engel[apos]s classification. Sixty-two patients were identified, 53% of patients were seizure-free (Engel Ia) and 79% had favorable outcome (Engel I [amp]II) after surgery. FCD type Ia was the most common histologically identified (64.5%) and temporal lobe was the most common location of type Ia (67.5%). FCD type IIb was commonly found in frontal and central lobe (83.3%). Magnetic resonance imaging study (MRI) identified FCD in 52.5% type Ia and 91.6% in type IIb. Temporal lobe FCD had a more favorable outcome than extratemporal FCD and the presence of balloon cells (type IIb) predicts good seizure outcome (91.6% of the patients with type IIb FCD were seizure free versus 57.5% for patients with type Ia cortical dysplasia). Surgical treatment of FCD can achieve seizure-free outcome in approximately half of the patients. Temporal lobe location and FCD type IIb predict good outcome.