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


METHODS
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.


RESULTS
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%).


CONCLUSIONS
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.
Chamberlain
Wendy A
WA
Department of Anatomic Pathology, Cleveland Clinic, Cleveland, Ohio, USA.
Cohen
Mark L
ML
Gyure
Kymberly A
KA
Kleinschmidt-DeMasters
Bette K
BK
Perry
Arie
A
Powell
Suzanne Z
SZ
Qian
Jiang
J
Staugaitis
Susan M
SM
Prayson
Richard A
RA
D002540:Cerebral Cortex / Q000473:pathology* / Q000601:surgery; D032921:Consensus; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005911:Gliosis / Q000473:pathology; D006801:Humans; D054220:Malformations of Cortical Development / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology*; D009474:Neurons / Q000473:pathology; D015588:Observer Variation; D010338:Pathology, Clinical; D015203:Reproducibility of Results; D009626:Terminology as Topic