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Hayakawa C, Kimura M, Kuroda Y, Hayashi S, Takeuchi K, Furukawa S. A case report of RccHan TM: WIST rat with multiple neoplastic and non-neoplastic proliferative lesions. J Toxicol Pathol 2021; 34:251-259. [PMID: 34290481 PMCID: PMC8280308 DOI: 10.1293/tox.2021-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/05/2021] [Indexed: 01/17/2023] Open
Abstract
It is extremely rare to have multiple spontaneous proliferative lesions in young adult rats. Here, we report the occurrence of different proliferative lesions in multiple tissues of a 7-week-old female rat in a 1-week repeated toxicity study. Grossly, multiple white patches and nodules in the bilateral kidneys, femoral and subcutaneous masses, and a nodule in the liver were observed. Renal lesions were diagnosed as renal mesenchymal tumors. One of the femoral subcutaneous masses was diagnosed as an adenolipoma consisting of mammary epithelial cells and mature adipocytes. The other femoral and abdominal subcutaneous masses were diagnosed as lipomas consisting of mature adipocytes. The liver nodule was diagnosed as non-regenerative hepatocellular hyperplasia, which was characterized by the proliferation of slightly hypertrophic hepatocytes. In the cauda equina, the growth of enlarged Schwann cells around the axon was observed, and this lesion was diagnosed as a neuroma.
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Affiliation(s)
- Chisato Hayakawa
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Masayuki Kimura
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Yusuke Kuroda
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Seigo Hayashi
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Kazuya Takeuchi
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Satoshi Furukawa
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
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