Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
Department of Pathology, Royal Hobart Hospital, Hobart, Australia.
Virchows Arch. 2020 Feb;476(2):323-327. doi: 10.1007/s00428-019-02644-3. Epub 2019 Aug 10.
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.
我们的目的是研究胸腺肿瘤中的皮脂分化，并确定新的可操作的基因组改变。为此，我们筛选了 35 例正常和 23 例增生胸腺、127 例胸腺瘤和 41 例胸腺癌，以确定形态和脂肪细胞分化蛋白和雄激素受体 (AR) 的表达是否存在皮脂分化。一个原发性胸腺癌表现出皮脂癌的形态学特征（角化和泡沫细胞、钙化、巨细胞），脂肪细胞分化蛋白和 AR 以及鳞状标志物表达强烈。NGS 显示成纤维细胞生长因子受体 2 (FGFR2) 高水平扩增。在胸腺和胸腺瘤中，不存在具有皮脂形态的细胞。偶尔，巨噬细胞或上皮细胞呈脂肪细胞分化蛋白阳性，但不与 AR 共表达。如果胸腺癌表现出明显的泡沫状特征，则应考虑胸腺皮脂癌。当在纵隔和其他部位寻找皮脂癌中的可操作的基因组改变时，检测 FGFR2 扩增可能是必要的。
