Spontaneous Renal Tumors Suspected of Being Familial in Sprague-Dawley
Rats |
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Authors: | Kayoko Kudo Toru Hoshiya Tomomi Nakazawa Tsubasa Saito Natsumi Shimoyama Isamu Suzuki Kazutoshi Tamura John Curtis Seely |
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Institution: | 1. Pathology Division, Gotemba Laboratory, Bozo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan;2. Experimental Pathology Laboratories Inc., Research Triangle Park, North Carolina, USA |
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Abstract: | Spontaneous renal tubule tumors (RTTs), with a distinctive morphological phenotype, were
present in three Sprague-Dawley rats, 1 male and 2 females, out a total of 120 animals of each
sex from untreated and placebo control groups in a 2-year carcinogenicity study. One female had
one carcinoma, adenoma and hyperplasia, and the other female had five adenomas and many
hyperplastic lesions; the male case had one carcinoma. From these cases, a biological continuum
of hyperplasia, adenoma and carcinoma could be recognized. The tumors were present in the renal
cortex and appeared as solid lobulated growths with occasional central necrosis. The lobules
were divided by a small amount of fibrovascular tissue. Occasionally the larger tumors
contained a cystic area. Tumor cells appeared distinctive and exhibited variable amounts of
eosinophilic/amphophilic and vacuolated cytoplasm. Nuclei were round to oval with a prominent
nucleolus. Mitotic figures were uncommon, and no distant metastasis was noted. The tumors were
seen as multiple and bilateral lesions in two animals and had no apparent relationship to
chronic progressive nephropathy (CPN). Foci of tubule hyperplasia were also noted to contain
the same type of cellular morphology. The morphological and biological features of these 3
cases resembled the amphophilic-vacuolar (AV) variant of RTT that has been posited to be of
familial origin. This is a report of spontaneous familial renal tumors in Sprague-Dawley rats
from Japan. |
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Keywords: | adenoma carcinoma familial kidney rats spontaneous |
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