Reproducibility of a Histogenetic Classification of Thymic Epithelial Tumours
A histogenetic classification of thymic epithelial neoplasms proposed by Müller-Hermelink and co-workers has been shown by a number of recent studies to be of clinical and prognostic value. Reproducibility is an important criterion for the acceptance of any new classification for general diagnostic use. The reproducibility of this classification was tested on 51 cases of thymic epithelial neoplasia, by comparing results obtained by pathologists working from published criteria only with results obtained by the pathologists who developed the classification. In 78% of cases there was complete concordance of results. Analysis of the 22% discordant cases showed that this discordance was due to a degree of subjectivity in determining cut-off points between categories adjacent to each other in the morphologic spectrum of thymic epithelial neoplasia (medullary vs mixed, cortical vs well-differentiated thymic carcinoma). In terms of the important clinical distinction between benign (medullary and mixed) thymomas and those with more aggressive biological behaviour (cortical types and well-differentiated thymic carcinoma), the degree of reproducibility was 96%. The high degree of reproducibility of this histogenetic classification of thymic epithelial neoplasms should facilitate its acceptance and use in routine diagnostic pathology.
KeywordsThymic Carcinoma Thymic Epithelial Cell Discordant Case Aggressive Biological Behaviour Thymic Epithelial Tumour
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- 5.Kornstein M. Controversies regarding the pathology of thymomas. Path Annu 1992; part 21-15.Google Scholar
- 10.Müller-Hermelink HK, Marino M, Palestro G. Pathology of thymic epithelial tumours. In: Müller-Hermelink HK, ed. Current Topics in Pathology: The Human Thymus. Berlin, Springer-Verlag, 1986:208–268.Google Scholar
- 11.Kirchner T, Müller-Hermelink HK. New approaches to the diagnosis of thymic epithelial tumors. Progress in Surgical Pathology 1989; 10; 167–189.Google Scholar
- 16.Close PM, Uys CJ. Thymic pathology: 32 years’ experience in Cape Town. Presented at the 3rd Meeting of the European Association for Haematopathology. Würzburg, Germany 7–11 October 1990. (Abstract)Google Scholar