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Interobserver variation in the classification of thymic tumours – a multicentre study using the WHO classification system
Author(s) -
Verghese E T,
Den Bakker M A,
Campbell A,
Hussein A,
Nicholson A G,
Rice A,
Corrin B,
Rassl D,
Langman G,
Monaghan H,
Gosney J,
Seet J,
Kerr K,
Suvarna S K,
Burke M,
Bishop P,
Pomplun S,
Willemsen S,
Addis B
Publication year - 2008
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2008.03088.x
Subject(s) - medicine , kappa , medical diagnosis , pathology , radiology , mathematics , geometry
Aims: To test the reproducibility of the current World Health Organization (WHO) classification of thymic epithelial tumours and to determine the level of interobserver variation within a group of pathologists, all with experience and expertise in thoracic pathology. Methods and results: Ninety‐five thymic tumours were circulated to a group of 17 pathologists in the UK and The Netherlands over a 1‐year period. Participants were asked to classify them according to WHO criteria. The diagnoses were subjected to statistical analysis and κ values calculated. The overall level of agreement was moderate (κ 0.45). When the categories were reduced in number by creating two groups, (A + AB + B1 + B2 and B3 + C), the level of agreement increased to 0.62. An alternative grouping (A + AB + B1 and B2 + B3 + C) increased it slightly further. The best agreement was in tumour types A and AB. Difficulties arose in distinguishing B1 tumours from B2 tumours and B2 tumours from B3 tumours. Conclusions: Although the WHO system describes a number of well‐defined tumour types with clear diagnostic criteria, the overall level of agreement was moderate and improved if some groups were amalgamated.