Michimae Yoshiko, Okimoto Kazuo, Toyosawa Kaoru, Matsumoto Izumi, Kouchi Mami, Tochitani Tomoaki, Koujitani Takatoshi, Funabashi Hitoshi, Seki Takaki
J Toxicol Pathol. 2012 Mar;25(1):4141-444. doi: 10.1293/tox.25.41.
A female congenic rat produced by repeated backcrossing of Nihon rats, a model for hereditary renal cell carcinoma, to Brown Norway rats was necropsied at 24 months of age. At necropsy, a white mass about 1 centimeter in size was observed in the thoracic cavity, and the mass partly adhered to the esophagus and the diaphragm. Histologically, the mass was clearly circumscribed by connective tissue, and consisted of neoplastic cuboidal epithelial cells that showed cystic tubular proliferation. Some islands of well-differentiated hepatocytes and some vessels were observed in the mass. Immunohistochemically, the tumor cells were strongly positive for cytokeratin and partly positive for vimentin but were negative for mesothelin and Von Willebrand Factor. The positive rate for Ki-67 was 2.4%. Based on these histological and immunohistochemical evidences, we diagnosed this tumor as a cystic cholangioma that might have arisen from the ectopic hepatic tissue in the thoracic cavity.
一只通过将遗传性肾细胞癌模型日本大鼠与棕色挪威大鼠反复回交培育出的雌性近交系大鼠，在24月龄时进行了尸检。尸检时，在胸腔内观察到一个大小约1厘米的白色肿块，该肿块部分附着于食管和膈肌。组织学上，肿块被结缔组织清晰地包绕，由显示囊性管状增生的肿瘤性立方上皮细胞组成。在肿块中观察到一些分化良好的肝细胞岛和一些血管。免疫组化显示，肿瘤细胞细胞角蛋白呈强阳性，波形蛋白部分阳性，但间皮素和血管性血友病因子呈阴性。Ki-67阳性率为2.4%。基于这些组织学和免疫组化证据，我们将该肿瘤诊断为可能起源于胸腔内异位肝组织的囊性胆管瘤。
