Thymoma, Lymphocytic, Rat

  • Mutsushi Matsuyama
Part of the Monographs on Pathology of Laboratory Animals book series (LABORATORY)


Large thymomas form a lobular mass occupying a large part of the thoracic cavity in old rats of susceptible strains, compressing the heart and lungs, and measuring 2–4 cm in diameter. In medium-sized thymomas, enlarged right and left lobes are usually demarcated by an anterior midline cleft. They are yellowish-white in color and soft in consistency. The surface is smooth, being surrounded by a distinct tissue capsule and clearly separated from the surrounding tissues. Small thymoma nodules may not be visible with the naked eye in younger rats of the susceptible strains because of their constitutively large thymuses, but they may be discernible in the involuted thymuses of Fl hybrid rats between the susceptible and resistant strains (Matsuyama et al.1988).


Benign thymoma epithelial thymoma 


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© Springer-Verlag Berlin Heidelberg 1990

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  • Mutsushi Matsuyama

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