13 research outputs found
Highly Metastatic Ovarian Yolk Sac Carcinoma in a Rat
We investigated a highly metastatic ovarian yolk sac carcinoma in a 52-week-old female
Crl:CD(SD) rat. Macroscopically, the present case had severe ascites, bilateral ovarian
masses and numerous nodules in the abdominal and thoracic cavities. Histopathologically,
these masses and nodules were generally composed of two types of cells mimicking a
parietal and visceral yolk sac. The parietal cells were round to polygonal, contained
eosinophilic droplets and were arranged in nests and cords in the eosinophilic matrix.
Both the intracytoplasmic droplets and the matrix were stained positively with PAS. The
visceral cells were cylindriform, and proliferated in papillary and tubular patterns and
occasionally formed Shiller-Duval body-like structures. In the dissemination sites, the
neoplastic cells proliferated on the surface of the various tissues and often infiltrated
into deeper parts of the tissues. Immunohistochemically, both neoplastic cells were
positive for α-fetoprotein and keratin, and the eosinophilic matrix was positive for
laminin. Ultrastructurally, the parietal cells had dilated rough endoplasmic reticulums,
which were filled with electron-lucent laminated structures. The visceral cells had poorly
to moderately developed intracytoplasmic organelles and were interconnected with
desmosomes. Taken together, the present tumor was diagnosed as yolk sac carcinoma arising
from the ovary and was characterized by not only high metastasis but also invasive
infiltration with biphasic proliferation of the parietal and visceral cells
ラットの中枢神経における自然発生性神経上皮性腫瘍と悪性細網症の病理学的研究
学位の種別: 論文博士審査委員会委員 : (主査)東京大学教授 中山 裕之, 東京大学教授 久和 茂, 東京大学准教授 角田 茂, 東京大学准教授 内田 和幸, 東京農工大学教授 渋谷 淳University of Tokyo(東京大学
Highly Invasive Intracranial Malignant Schwannoma in a Rat
A highly invasive intracranial malignant schwannoma containing several masses was detected in a 28-week-old male Crl:CD(SD) rat. Macroscopically, 3 masses were noted in the cranial cavity; one was present at the bottom of the cranial cavity and involved the trigeminal nerve, and the other two were in the parietal bone. Histologically, each mass consisted of fusiform cells with interlacing fascicular, wavy and nuclear pseudopalisading arrangements and round cells with cystic lesions. The tumor cells invaded not only the brain but also the parietal bone. In the brain, the tumor cells infiltrated diffusely into the leptomeningeal and perivascular spaces and parenchyma, in which the tumor cell morphology and invasive pattern closely resembled those of malignant astrocytoma and malignant reticulosis. Immunohistochemically, the tumor cells in the masses showed positive reactions for both S-100 protein and GFAP, while those in the cerebral invasion sites were negative for GFAP and less positive for S-100 protein. Electron microscopically, a single basal lamina layer and short intricate cell processes were confirmed in the tumor cells. From these results, the present tumor was diagnosed as a malignant schwannoma arising in the cranial cavity, probably originating from the trigeminal nerve. The present tumor is considered to be a relatively unique malignant schwannoma based on its growth and invasion patterns
Availability of a Microglia and Macrophage Marker, Iba-1, for Differential Diagnosis of Spontaneous Malignant Reticuloses from Astrocytomas in Rats
Transition of Historical Control Data for High Incidence Tumors in F344 Rats
data (from 1990 to 2004, previously reported) in the same facility. In the results, the incidence of C-cell adenoma in the thyroid tended to increase in both sexes in recent years (30.8 % for males and 24.4 % for females in 2005-2009) as compared with the previous data (17.4 % and 20.1 % for males and 11.5 % and 11.8 % for females in 1990–1999 and 2000–2004, respectively). In addition, the incidences of pancreatic islet cell adenoma in males and uterine adenocarcinoma tended to increase from around 2000 and remained high in recent years (incidences of islet cell adenoma in males of 10.5%, 17.1 % and 20.5 % in 1990–1999, 2000–2004 and 2005–2009; incidences of uterine adenocarcinoma of 3.3%, 12.0 % and 13.5 % in 1990–1999, 2000–2004 and 2005–2009, respectively). There was no apparent difference in the incidence of other tumors. (DOI: 10.1293/tox.26.227; J Toxicol Pathol 2013; 26: 227–230) Key words: historical control data, F344 rat, high incidence tumo