Kuzutani Kazuya, Shibanushi Toshiyuki, Kangawa Yumi, Kihara Tohru
Kaken Pharmaceutical Co., Ltd., Pharmacokinetics and Safety Research Department, 301 Gensuke, Fujieda-Shi,Shizuoka 426-8646, Japan.
J Toxicol Pathol. 2012 Sep;25(3):221-4. doi: 10.1293/tox.25.221. Epub 2012 Oct 1.
Spontaneous mammary adenocarcinoma was observed in a 12-week-old female SD rat. A movable mass in the right cervical region was found at 11 weeks of age, and the rat was sacrificed the following week. The mass was located in the vicinity of the right salivary gland and measured 38 mm × 26 mm × 16 mm in gross size. It was a firm whitish mass, with a cut surface that was also whitish in appearance. Histopathologically, neoplastic cells formed glandular structures that contained secreted eosinophilic material. Ultrastructurally, similar secreted material and lipid droplets were in the cytoplasm of the neoplastic cells. Immunohistochemically, the neoplastic cells were positive for cytokeratin 8, cytokeratin 18 and estrogen receptor α. Based on these findings, the tumor was diagnosed as a mammary gland adenocarcinoma, and we therefore conclude that this tumor type can occur spontaneously in female SD rats as young as 12 weeks of age.
在一只12周龄的雌性SD大鼠中观察到自发性乳腺腺癌。该大鼠在11周龄时发现右颈部有一个可移动的肿块，于接下来的一周处死。肿块位于右唾液腺附近，大体尺寸为38 mm×26 mm×16 mm。它是一个质地坚实的白色肿块，切面外观也呈白色。组织病理学检查显示，肿瘤细胞形成了含有分泌性嗜酸性物质的腺管结构。超微结构检查发现，肿瘤细胞的细胞质中存在类似的分泌物质和脂滴。免疫组织化学检查显示，肿瘤细胞细胞角蛋白8、细胞角蛋白18和雌激素受体α呈阳性。基于这些发现，该肿瘤被诊断为乳腺腺癌，因此我们得出结论，这种肿瘤类型可在年仅12周龄的雌性SD大鼠中自发发生。
