A morphological study off a thyroid carcinoma in a medaka, Oryzias latipes (Temminck & Schlegel) |
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| Authors: | T Harada H Itoh J Hatanaka S Kamiya M Enomoto |
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| Institution: | Division of Biology;Department of Veterinary Anatomy, Nippon Veterinary and Animal Science University, Tokyo, Japan;Department of Pathology, Biosafety Research Center, Foods, Drugs, and Pesticides, Shizuoka, Japan |
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| Abstract: | A large mass protruding beyond the left operculum was found in an adult male medaka, Oryzias latipes (Temminck & Schlegel). Histologically, the mass was mainly composed of thyroid follicles measuring up to 292 μm in diameter. The follicular epithelium consisted of cuboidal or squamous cells. The follicles lacked colloidal material in the lumen. The thyroid tissue infiltrated into the kidney. Electron microscopically, the tumour cells were characterized by dilation and vesiculation of rough endoplasmic reticulum, which extended throughout the cytoplasm, and an irregular outline of the nucleus. Mitotic figures and partly degenerate cells were frequently observed. Based on the above features, the tumour was diagnosed as a follicular carcinoma of the thyroid, the first reported case in the medaka. |
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