Abstract: Canine lymphosarcoma also known as malignant lymphoma is one of the most common tumors in canine tumors. A series of detailed clinical examinations for an eight-year-old dog with a spleen tumor was conducted, such as routine clinical examination, X-ray examination, hematology examination and pathological histology examination and then the splenic tumors were removed by exploratory laparotomy and pathological histology examination was carried out. Histopathological observation showed that lymphoid cells were patchy, round or nearly round, with a small amount of reticular collagen fibers in the stroma, few cytoplasm, hyperchromatic nuclei and more mitotic phenomena. There were hemorrhage and hemosiderin cells in the stroma and multiple necrotic foci in the center, thus diagnosing malignant lymphosarcoma of the spleen and providing basis for the treatment and prognosis of the disease.

Key words: canine, spleen, lymphosarcoma, histopathology