Interobserver and intraobserver reproducibility in focal cortical dysplasia (malformations of cortical development)

Department of Anatomic Pathology, Cleveland Clinic, Cleveland, Ohio, USA.
Epilepsia (Impact Factor: 4.58). 10/2009; 50(12):2593-8. DOI: 10.1111/j.1528-1167.2009.02344.x
Source: PubMed

ABSTRACT Malformations of cortical development (MCD) (cortical dysplasias) are well-recognized causes of intractable epilepsy. Although a histologic classification system for MCD has been proposed by Palmini et al. (Neurology; 2004; 62:S2), studies to date have not assessed reproducibility. The purpose of this study was to analyze inter- and intraobserver agreement among eight experienced neuropathologists (NPs) with respect to this classification system.
Sections from 26 epilepsy resections were selected to represent the range of pathologies described by Palmini et al. Recuts of single sections from each case were sent to the NPs to classify. The slides were resent at a later date for reclassification. Kappa analysis for both inter- and intraobserver concordance was performed.
Interobserver agreement was moderate (kappa = 0.4968). There was > or =62.5% (5 of 8 NPs) agreement for 19 of 26 cases. The greatest concordance was present when making focal cortical dysplasia (FCD) types IIA/B classifications (12 of the 14 cases with > or =75% consensus). Mild MCD (types I/II) and FCD types IA/B classifications were the least reproducible, and used most frequently in cases without consensus. Intraobserver concordance was moderate to very good (range kappa = 0.4654-0.8504). The category with the fewest classification changes made on reevaluation was FCD type IIB (4.2%), whereas that with the most changes was mild MCD (types I/II) (52.9%).
Interobserver concordance using this approach was moderate. The classification categories with the greatest concordance were FCD type IIA/B, and the least, mild MCD and FCD types IA/B. In addition, difficulty in differentiating Mild MCD/FCD type I lesions from normal and/or gliotic tissue was noted.

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    • "It was revisited by an ILAE Task Force in 2011, for the reason that some histopathology definitions of FCD subtypes were not proven reliable. As a prominent example, in an agreement study among nine North American neuropathologists , least agreement was achieved when judging Palmini FCD type Ib, reflecting the challenge to properly distinguish this subtype from normal cortical tissue (Chamberlain et al., 2009). It was the consensus of the ILAE Task Force to propose a classification system relying on careful histopathologic evaluation, giving at hand a microscopic description of histology features to better distinguish FCD subtypes. "
    Epilepsia 08/2013; 54(8):1506-7. DOI:10.1111/epi.12254 · 4.58 Impact Factor
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    • "The prevalence of pharmacoresistant epilepsy in NF1 is low and the number of patients undergoing surgical treatment, and histopathological studies , is consequently small (0.5% of all epilepsy surgery cases in our study). Interobserver concordance among neuropathologists was high (10 of 12 patients), when compared to previous reports on intra and interobserver reproducibility in the classification of dysplastic lesions (Chamberlain et al., 2009) and brain tumours (Gilles et al., 2008), The only two discordant diagnoses might be related to different classification attitudes among neuropathologists (Chamberlain et al., 2009; Gilles et al., 2008). Sixty-six percent of our patients were cognitively impaired. "
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    ABSTRACT: Epilepsy is relatively uncommon in patients with Neurofibromatosis Type 1 (NF1) and seizures are usually well controlled with antiepileptic treatment. However, pharmacoresistance has been reported in patients with NF1 and MRI evidence of malformations of cortical development or glioneuronal tumours. Available information on epilepsy surgery in NF1 is limited to a few patients with gliomas and glioneuronal tumours who underwent lesionectomies. We conducted a survey amongst 25 European epilepsy surgery centres to collect patients with NF1 who had undergone surgery for drug-resistant seizures and identified 12 patients from eight centres. MRI abnormalities were present in all patients but one. They were unilateral temporal in eight, bilateral temporal in one and multilobar or hemispheric in two. Seizures originated from the temporal lobe in ten patients, from the temporo-parieto-occipital region in one, and were bitemporal in one. One year after surgery eight patients were seizure free, one had worthwhile improvement and the remaining three had experienced no benefit. Postoperative outcome, available at 2 years in ten patients and at 5 years in three, remained stable in all but one whose seizures reappeared. Histology revealed dysembryoplastic neuroepithelial tumour (DNET) in five patients, hippocampal sclerosis in four, mixed pathology in one and polymicrogyria in one. No histological abnormality was observed in the remaining patient. Epilepsy surgery can be performed effectively in patients with NF1 provided a single and well-delimited epileptogenic zone is recognized. The high prevalence of DNETs in this series might suggest a non-fortuitous association with NF1.
    Epilepsy research 04/2013; 105(3). DOI:10.1016/j.eplepsyres.2013.02.021 · 2.19 Impact Factor
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    • "Greatest concordance was accounted for in FCD types IIa/b, whereas the classification of Palmini's FCD types Ia and Ib remained challenging. Mild MCDs (mMCDs) were also included in their trial but least reproducible (Chamberlain et al., 2009). Our survey reached a higher j value of 0.6532 for interobserver consensus among an international group of nine neuropathologists. "
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    ABSTRACT: An International League Against Epilepsy (ILAE) consensus classification system for focal cortical dysplasias (FCDs) has been published in 2011 specifying clinicopathologic FCD variants. The aim of the present work was to microscopically assess interobserver agreement and intraobserver reproducibility for FCD categories among an international group of neuropathologists with different levels of experience and access to epilepsy surgery tissue. Surgical FCD specimens covering a broad histopathology spectrum were retrieved from 22 patients with epilepsy. Three surgical nonepilepsy specimens served as controls. A total of 188 slides with routine or immunohistochemical stainings were digitalized with a slide scanner to allow Internet-based microscopy review. Nine experienced neuropathologists were invited to review these cases twice at a time gap of 3 months and different orders of case presentation. The 2011 ILAE FCD consensus classification served as instruction. Kappa analysis was calculated to estimate interobserver and intraobserver agreement levels. In a third evaluation round, 21 additional neuropathologists with different experience and access to epilepsy surgery reviewed the same case series. Interobserver agreement was good (κ = 0.6360), with 84% consensus of diagnoses during the first evaluation (21 of 25 cases). Kappa values increased to 0.6532 after reevaluation, and consensus was obtained in 24 (96%) of 25 cases. Overall intraobserver reproducibility was also good (κ = 0.7824, ranging from 0.4991 to 1.000). Fewest changes in the classification were made in the FCD type II group (2.2% of 225 original diagnoses), whereas the majority of changes occurred in FCD type III (13.7% of 225 original diagnoses). In the third evaluation round, interobserver agreement was reflected by the level of experience of each neuropathologist, with κ values ranging from moderate (0.5056; high level of experience >40 cases/year) to low (0.3265; low level of experience <10 cases/year). Our study achieved a good and reliable interobserver agreement among the group of expert neuropathologists originally involved in the ILAE FCD consensus classification system. Intraobserver reproducibility in this group was even more robust. These results showed considerable improvement compared to a previous study evaluating the 2004 Palmini FCD classification. Agreement levels were lower in our second group of neuropathologists and were related to their level of access and experience with epilepsy surgery specimens. These results suggested that the more precise ILAE definition of FCD histopathology patterns improves operational procedures in the diagnosis of FCDs. On the other hand, microscopic assessment of FCD is a challenge and requires sustained experience and teaching. The virtual slide review system allowed testing of this hypothesis and reached a widespread group of participating colleagues from different centers all over the world. We propose to further use this tool as a teaching device and also to address other epilepsy-associated entities still difficult to classify such as hippocampal sclerosis, long-term epilepsy-associated tumors, or mild malformations of cortical development (mMCDs), which were not yet covered by current ILAE classification systems.
    Epilepsia 05/2012; 53(8):1341-8. DOI:10.1111/j.1528-1167.2012.03508.x · 4.58 Impact Factor
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