Abstract
An 8-year-old castrated male mixed-breed cat presented with an abdominal mass of unknown origin, accompanied by eosinophilia. Autopsy revealed mild-to-severe enlargement of lymph nodes throughout the body and multiple nodules in the lungs. Histopathologically, the lymph nodes showed severe fibroplasia and infiltration by a large number of eosinophils and fewer tumor cells, exhibiting large-sized lymphoid cell morphology. Metastatic lesions of tumor cells with eosinophilic infiltration and fibrosis were observed in the lungs, liver, kidneys, stomach, and intestines. Immunohistochemistry revealed that the tumor cells were positive for CD3 and negative for B cell and mast cell markers. Thus, T-cell lymphoma with eosinophilic infiltration and sclerosing fibroplasia was diagnosed.