Our aim was to investigate sebaceous differentiation in thymus tumours and to identify new actionable genomic alterations. To this end we screened 35 normal and 23 hyperplastic thymuses, 127 thymomas and 41 thymic carcinomas for the presence of sebaceous differentiation as defined by morphology and expression of adipophilin and androgen receptor (AR). One primary thymic carcinoma showed morphology of sebaceous carcinomas (keratinizing and foam cells, calcifications, giant cells), a strong expression of adipophilin and AR together with squamous markers. NGS revealed high-level amplification of fibroblast growth factor receptor 2 (FGFR2). In thymuses and thymomas, no cells with sebaceous morphology were present. Occasionally, macrophages or epithelial cells showed adipophilin-positivity, however, without co-expression of AR. Thymic sebaceous carcinoma should be considered if a thymic carcinoma shows clear or foamy features. Testing for FGFR2 amplification might be warranted when searching for actionable genomic alterations in sebaceous carcinomas in the mediastinum and in other locations.

Item Type:	Refereed Article
Keywords:	adipophilin, BRCA2, FGFR2, sebaceous carcinoma, thymus carcinoma
Research Division:	Biomedical and Clinical Sciences
Research Group:	Clinical sciences
Research Field:	Pathology (excl. oral pathology)
Objective Division:	Health
Objective Group:	Clinical health
Objective Field:	Clinical health not elsewhere classified
UTAS Author:	Ochi, A (Miss Ayame Ochi)
ID Code:	134622
Year Published:	2020 (online first 2019)
Web of Science® Times Cited:	3
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2019-08-22
Last Modified:	2022-08-29
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