1 research outputs found
Interobserver variation in the classification of thymic lesions including biopsies and resection specimens in an international digital microscopy panel
Aims: Thymic tumours are rare in routine pathology
practice. Although the World Health Organization
(WHO) classification describes a number of well-defined categories, the classification remains challenging. The aim of this study was to investigate the
reproducibility of the WHO classification among a
large group of international pathologists with expertise in thymic pathology and by using whole slide
imaging to facilitate rapid diagnostic turnover.
Methods and results: Three hundred and five tumours,
consisting of 90 biopsies and 215 resection specimens,
were reviewed with a panel-based virtual microscopy
approach by a group of 13 pathologists with expertise in
thymic tumours over a period of 6 years. The specimens
were classified according to the WHO 2015 classification.
The data were subjected to statistical analysis, and interobserver concordance (Fleiss kappa) was calculated. All
cases were diagnosed within a time frame of 2 weeks. The
overall level of agreement was substantial (j = 0.6762),
and differed slightly between resection specimens
(j = 0.7281) and biopsies (j = 0.5955). When analysis
was limited to thymomas only, and they were grouped
according to the European Society for Medical Oncology
Clinical Practice Guidelines into B2, B3 versus A, AB, B1
and B3 versus A, AB, B1, B2, the level of agreement
decreased slightly (j = 0.5506 and j = 0.4929, respectively). Difficulties arose in distinguishing thymoma from
thymic carcinoma. Within the thymoma subgroup, difficulties in distinction were seen within the B group.
Conclusions: Agreement in diagnosing thymic lesions
is substantial when they are assessed by pathologists
with experience of these rare tumours. Digital pathology decreases the turnaround time and facilitates
access to what is essentially a multinational resource.
This platform provides a template for de