Clinical characteristics, pathological features and surgical outcomes of focal cortical dysplasia (FCD) type II: correlation with pathological subtypes

Abstract

Focal cortical dysplasia (FCD) type II is a major cause of drug-resistant epilepsy. In order to gain insight into the possible correlations between FCD II pathological pattern and different clinical characteristics (including clinical information, imaging characteristics and surgical outcomes), different clinicopathological characteristics in two types of FCD II were analyzed (especially in FCD IIb). The mean age of seizure onset and disease duration of 78 patients was 11.0 and 11.2 years, respectively. Patients with FCD type IIb had earlier seizure onset compared with those with FCD type IIa. Pathological subtype IIb was predominantly in frontal lobe and subtype IIa was predominantly seen in temporal. Type IIb demonstrated significantly more signal abnormalities in fluid attenuated inversion recovery (FLAIR) images and T2 images than Type IIa. The rate of satisfactory seizure outcome was 67.64 % in the FCD IIa group, while relative higher, 88.63 %, in the FCD IIb group. All these characteristics may assist in their earlier diagnosis and improve the predictability of surgical management.

Radiologic and Pathologic Features of the Transmantle Sign in Focal Cortical Dysplasia: The T1 Signal Is Useful for Differentiating Subtypes

“…Compared with other FCDs without the TMS, the presence of the TMS indicated a high likelihood of a seizure-free outcome. 20,21 Detecting these lesions during a preoperative examination is important for surgical decision-making and improving postoperative outcomes. 1,22,23 If the preoperative MR imaging indicates type IIb, a favorable prognosis can be expected after surgery.…”

Polymorphous low-grade neuroepithelial tumor of the young: case report and review focus on the radiological features and genetic alterations

“…In general, the extent of the lesion is smaller than the other epileptogenic tumors. Focal cortical thickening, blurry gray white matter interface, focally increased signal on T2WI and the "transmantle" sign are the MR characteristics of FCD [11,12]. Interestingly, FCD Ib was observed in the transition region in one of our cases, which might imply the homogeneous genetic origination of PLNTY and FCD.…”

Focal cortical dysplasia: Molecular disturbances and clinicopathological classification (Review)

“…The study by Simpson and Prayson, taking into consideration the ILAE classification, including the new FCD IC subtype, did not reveal any differences in Engel I rate after surgery, which was 48%, in all three FCD I subtypes (82). The outcome in FCD II cases is better, it fluctuates between 50-88% (40,71). There is a higher seizure outcome in FCD IIB, compared to FCD IIA, and there is no correlation between outcome and age at onset or the duration of epilepsy (71).…”

“…Adult-onset epilepsy in most studies is limited to several cases (38,39). Seizures are generally of high frequency, up to dozens a day (40) and can be localised or generalise secondarily. A recent study comparing the characteristics of patients with FCD and epilepsy onset in the first year showed that the presence epileptic spasms is connected with the frontal lobe localisation of the lesion (41).…”

“…A recent FCD II subgroup analysis pointed out that FCD IIB patients have an earlier epilepsy onset in comparison with FCD IIA patients. Subtype IIB was observed predominantly in the frontal lobe and subtype IIA was more often observed in the temporal lobe (40). In cases where cortical lamination abnormalities co-exist with the principal lesion, such as glial or glioneuronal tumours (FCD IIIB), the frequency of seizures reaches 100%, particularly when the tumour is slow-growing (43).…”