Kijima Kei, Suehiro-Narita Miki, Ito Shino, Shiraki Ayako, Nii Aisuke
Central Research Laboratory, Research & Development, Seikagaku Corporation, 1253 Tateno 3-chome, Higashiyamato-shi, Tokyo 207-0021, Japan.
J Toxicol Pathol. 2021 Jul;34(3):235-239. doi: 10.1293/tox.2020-0073. Epub 2021 Apr 16.
We encountered a case of spontaneous thymic carcinosarcoma in a young Crl:CD (Sprague Dawley) rat. Grossly, a white multinodular mass replaced the thymus in the thoracic cavity. Histologically, multiple nodules were separated by fibrous stroma, and each nodule included isolated regions that were composed of epithelial or non-epithelial tumor cells. The epithelial tumor cells were relatively large and round to polygonal cells with large nuclei and weakly eosinophilic cytoplasm. These cells were cytokeratin-positive and vimentin-negative. These cells infiltrated the lungs. The non-epithelial tumor cells were poorly differentiated, small, round to spindle-shaped cells with small nuclei and basophilic cytoplasm. These cells were vimentin-positive and mostly cytokeratin-negative. Many islands of cartilage were observed near non-epithelial cells. Based on these findings, the tumor was diagnosed as a primary thymic carcinosarcoma consisting of a malignant thymoma composed of epithelial tumor cells and a mesenchymal chondrosarcoma composed of non-epithelial tumor cells.
我们在一只年轻的Crl:CD（斯普拉格-道利）大鼠中遇到了一例自发性胸腺癌肉瘤病例。大体上，一个白色多结节肿块取代了胸腔内的胸腺。组织学上，多个结节被纤维性间质分隔，每个结节包含由上皮或非上皮肿瘤细胞组成的孤立区域。上皮肿瘤细胞相对较大，呈圆形至多边形，细胞核大，细胞质弱嗜酸性。这些细胞细胞角蛋白阳性，波形蛋白阴性。这些细胞浸润到肺部。非上皮肿瘤细胞分化差，小，呈圆形至梭形，细胞核小，细胞质嗜碱性。这些细胞波形蛋白阳性，大多细胞角蛋白阴性。在非上皮细胞附近观察到许多软骨岛。基于这些发现，该肿瘤被诊断为原发性胸腺癌肉瘤，由上皮肿瘤细胞组成的恶性胸腺瘤和非上皮肿瘤细胞组成的间叶性软骨肉瘤构成。
