Luka Brcic, Gregor Vlacic, Franz Quehenberger, Izidor Kern1. 1. From the Institute of Pathology (Dr Brcic) and the Institute for Medical Informatics, Statistics and Documentation (Dr Quehenberger), Medical University of Graz, Graz, Austria; and Cytology and Pathology Laboratory, University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia (Drs Vlacic and Kern).
Abstract
CONTEXT: - Malignant pleural mesothelioma (MPM) is a rare tumor with poor prognosis. Several studies have analyzed potential prognostic markers, but histologic type remains the single most important prognostic factor. Histologic subtypes of epithelioid MPM seem to have prognostic and therapeutic implications. Interobserver agreement in histologic pattern classification should be high. OBJECTIVE: - To assess interobserver and intraobserver reproducibility in histologic differentiation between the main types of MPMs, and in further subtyping of epithelioid-type mesothelioma. DESIGN: - One representative hematoxylin-eosin-stained slide was selected from the archive for each of 200 patients with MPM. They were reviewed independently by 3 pathologists and classified according to the current World Health Organization classification of pleural tumors. After the first round of evaluations, a consensus meeting was organized where problems were addressed and representative images for each histologic category were selected. Two months later, cases were reevaluated by all 3 pathologists. RESULTS: - After the first round, overall interobserver agreement for histologic subtyping of mesothelioma was fair (κ, 0.36). The agreement was increased to substantial (κ, 0.63) in the second round. Improvement was found in interobserver agreement for all types of MPM and for most epithelioid subtypes. CONCLUSIONS: - Moderate to substantial agreement in histologic typing and subtyping of MPM can be achieved. However, training with additional clarification of diagnostic criteria, their strict application, and help from consensus-based illustrative images is needed.
CONTEXT: - Malignant pleural mesothelioma (MPM) is a rare tumor with poor prognosis. Several studies have analyzed potential prognostic markers, but histologic type remains the single most important prognostic factor. Histologic subtypes of epithelioid MPM seem to have prognostic and therapeutic implications. Interobserver agreement in histologic pattern classification should be high. OBJECTIVE: - To assess interobserver and intraobserver reproducibility in histologic differentiation between the main types of MPMs, and in further subtyping of epithelioid-type mesothelioma. DESIGN: - One representative hematoxylin-eosin-stained slide was selected from the archive for each of 200 patients with MPM. They were reviewed independently by 3 pathologists and classified according to the current World Health Organization classification of pleural tumors. After the first round of evaluations, a consensus meeting was organized where problems were addressed and representative images for each histologic category were selected. Two months later, cases were reevaluated by all 3 pathologists. RESULTS: - After the first round, overall interobserver agreement for histologic subtyping of mesothelioma was fair (κ, 0.36). The agreement was increased to substantial (κ, 0.63) in the second round. Improvement was found in interobserver agreement for all types of MPM and for most epithelioid subtypes. CONCLUSIONS: - Moderate to substantial agreement in histologic typing and subtyping of MPM can be achieved. However, training with additional clarification of diagnostic criteria, their strict application, and help from consensus-based illustrative images is needed.
Authors: Jasleen K Grewal; Basile Tessier-Cloutier; Martin Jones; Sitanshu Gakkhar; Yussanne Ma; Richard Moore; Andrew J Mungall; Yongjun Zhao; Michael D Taylor; Karen Gelmon; Howard Lim; Daniel Renouf; Janessa Laskin; Marco Marra; Stephen Yip; Steven J M Jones Journal: JAMA Netw Open Date: 2019-04-05