Terayama Yui, Matsuura Tetsuro, Ozaki Kiyokazu
Laboratory of Pathology, Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan.
J Toxicol Pathol. 2022 Apr;35(2):205-209. doi: 10.1293/tox.2021-0067. Epub 2022 Jan 1.
Primary splenic stromal tumors have rarely been reported in rodents. We report the case of a 90-week-old male WBN/Kob rat with a nodular demarcated mass in the spleen, which was kept as a non-treated animal in a long-term animal study. Histopathology revealed round to short spindle-shaped tumor cells arranged in a solid growth pattern. Invasive growth, anisokaryosis, and high mitotic activity (46 per 10 high-power fields [2.37 mm]) were observed to be multifocal, but most tumor cells showed mild nuclear pleomorphism. The pattern of silver impregnation corresponded to that of the marginal zone of the red pulp. Immunohistochemistry revealed that the tumor cells were double positive for fascin and desmin and focally positive for Iba-1 and OX-6 expression. These characteristics were similar to those observed in fibroblastic reticular cells and dendritic cells in the marginal zone of the red pulp. These findings suggest that the malignant stromal cell tumor of the spleen in this case had characteristics of both fibroblastic reticular cells and dendritic cells.
原发性脾脏间质肿瘤在啮齿动物中鲜有报道。我们报告了一例90周龄雄性WBN/Kob大鼠，其脾脏有一个边界清晰的结节状肿块，该大鼠在一项长期动物研究中作为未治疗动物饲养。组织病理学显示，肿瘤细胞呈圆形至短梭形，呈实体生长模式。观察到多灶性侵袭性生长、核大小不等和高有丝分裂活性（每10个高倍视野[2.37毫米]中有46个），但大多数肿瘤细胞显示轻度核多形性。银浸染模式与红髓边缘区的模式一致。免疫组织化学显示，肿瘤细胞对fascin和结蛋白呈双阳性，对Iba-1和OX-6表达呈局灶性阳性。这些特征与红髓边缘区的成纤维网状细胞和树突状细胞中观察到的特征相似。这些发现表明，该病例中脾脏的恶性间质细胞瘤具有成纤维网状细胞和树突状细胞的特征。
