Spontaneous thymic lymphomas in the non-obese diabetic/Shi-scid, IL-2Rγnull mouse

The NOD/Shi-scid, IL-2Rγnull (NOG) mouse is a severely immunodeficient mouse used for the engraftment of human tissues and cells. In this study, 2406 mice (8–62 weeks old, 503 males and 1903 females) were subcutaneously engrafted with human tissues. In 16 mice (12–26 weeks old, 1 male and 15 females), a mass was seen in the anteroventralis of the thorax on gross examination with an incidence of 0.7%. Histologically, the masses were composed of sheets of lymphoblastic cells. A ‘starry sky’ pattern was observed with numerous mitoses. Immunohistochemically the lymphoblastic cells were positive for Thy 1. The lymphoblastic cells were also seen in the spleen, lung, liver, kidney and heart. The gross and histopathological findings led to the diagnosis of spontaneous thymic lymphoma in NOG mice.