Ito Tsuyoshi, Yoshida Toshinori, Soma Katsumi, Katoh Yoshitaka, Shimada Yuko, Ohnuma-Koyama Aya, Takahashi Naofumi, Okazaki Yoshimasa, Shiga Atsushi, Kuwahara Maki, Harada Takanori
The Institute of Environmental Toxicology, 4321 Uchimoriya-machi, Joso-shi, Ibaraki 303-0043, Japan.
Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo183-8509, Japan.
J Toxicol Pathol. 2017 Jul;30(3):245-250. doi: 10.1293/tox.2016-0080. Epub 2017 Apr 27.
We report a female Crlj:CD1(ICR) mouse with a spontaneous mammary gland tumor composed of biphasic tumor cells, i.e., epithelioid and spindle-shaped myoepithelial cells. Macroscopically, a subcutaneous mass, approximately 3 cm in diameter was found in the lumbodorsal region. Histopathologically, the epithelioid cells proliferated in an alveolar or nest-like growth pattern, occasionally forming glandular-like structures. On the other hand, the spindle-shaped cells proliferated in a sarcomatous pattern. Normal mammary gland was observed in the vicinity of the tumor. Both types of tumor cells showed immunoreactivity for cytokeratin (wide spectrum screening), vimentin, S100, and p63. In addition, the epithelioid cells and spindle-shaped cells were immunopositive for glial fibrillary acidic protein and smooth muscle actin, respectively. Moderate atypia, high proliferative activity, massive necrosis, and partial infiltration to the surrounding tissues were also observed. We made a diagnosis of myoepithelial carcinoma, which is extremely rare in ICR mice.
我们报告了一只雌性Crlj:CD1(ICR)小鼠，其患有由双相肿瘤细胞（即上皮样细胞和梭形肌上皮细胞）组成的自发性乳腺肿瘤。宏观上，在腰背部区域发现一个直径约3 cm的皮下肿块。组织病理学上，上皮样细胞以腺泡状或巢状生长模式增殖，偶尔形成腺管样结构。另一方面，梭形细胞以肉瘤样模式增殖。在肿瘤附近观察到正常乳腺组织。两种类型的肿瘤细胞对细胞角蛋白（广谱筛查）、波形蛋白、S100和p63均呈免疫反应性。此外，上皮样细胞和梭形细胞分别对胶质纤维酸性蛋白和平滑肌肌动蛋白呈免疫阳性。还观察到中度异型性、高增殖活性、大片坏死以及对周围组织的部分浸润。我们诊断为肌上皮癌，这在ICR小鼠中极为罕见。
