Nagaike Mika, Sakai Kimie, Tsuchiya Seiichiro, Shimada Fumi, Inui Kosei, Uratani Mamoru
Safety Science Laboratory, Central Research Institute, Ishihara Sangyo Kaisha Ltd., 2-3-1 Nishishibukawa, Kusatsu-shi, Shiga 525-0025, Japan.
J Toxicol Pathol. 2011 Mar;24(1):75-9. doi: 10.1293/tox.24.75. Epub 2011 Mar 31.
A subcutaneous mass in the right femoral region of a female F344 Slc/N rat was examined histopathologically. At 83 weeks of age, the animal showed symptoms of severe anemia and nasal bleeding. Necropsy revealed that the mass had invaded the skeletal muscles but did not affect the bones. Multicentric nodules were also observed in the lung. Histopathology revealed a sheet-like growth pattern of polygonal tumor cells with round or comma-shaped nuclei and pale eosinophilic cytoplasm. Osteoid tissue was observed in not only the original lesion but also the metastatic foci in the lung. Each tumor cell was surrounded by argentophil fibers and few collagen fibers. Immunohistochemically, the tumor cells were positive for proliferating cell nuclear antigen (PCNA), vimentin, osterix and osteocalcin, but negative for keratin, S-100, von Willebrand factor, CD-31, CD-34, desmin, α-smooth muscle actin, lysozyme, α1-antitrypsin and rat malignant fibrous histiocytoma (MFH) antigen. CD-68-positive cells were considered to be infiltrated macrophages because they were negative for PCNA. On the basis of these findings, we diagnosed the present case as extraskeletal osteosarcoma.
对一只雌性F344 Slc/N大鼠右股部的皮下肿块进行了组织病理学检查。在83周龄时，该动物出现严重贫血和鼻出血症状。尸检发现肿块已侵犯骨骼肌，但未影响骨骼。在肺部也观察到多中心结节。组织病理学显示，多边形肿瘤细胞呈片状生长模式，细胞核呈圆形或逗号形，细胞质呈淡嗜酸性。不仅在原发灶，而且在肺部转移灶中均观察到类骨质组织。每个肿瘤细胞被嗜银纤维和少量胶原纤维包围。免疫组织化学检查显示，肿瘤细胞增殖细胞核抗原（PCNA）、波形蛋白、osterix和骨钙素呈阳性，但角蛋白、S-100、血管性血友病因子、CD-31、CD-34、结蛋白、α-平滑肌肌动蛋白、溶菌酶、α1-抗胰蛋白酶和大鼠恶性纤维组织细胞瘤（MFH）抗原呈阴性。CD-68阳性细胞被认为是浸润的巨噬细胞，因为它们PCNA呈阴性。基于这些发现，我们将本病例诊断为骨外骨肉瘤。
