Lymphosarcoma in a raccoon (Procyon lotor)

A case of lymphosarcoma in a captive adult female raccoon (Procyon lotor) from northeastern Pennsylvania (USA) was observed in 1991. Prior to its death the raccoon had lost weight. At necropsy the carcass was in poor body condition and had pale mucous membranes. The thoracic and abdominal lymph nodes were enlarged, soft, and pale tan. Microscopically, there was effacement of normal lymph node architecture by sheets of mononuclear cells. These were well-differentiated small lymphocytes with distinct cell borders. Nuclei of these cells were darkly stained and mitotic figures were frequently seen. Similar but lesser numbers of neoplastic cells were seen in the parenchyma of liver, spleen, and the pancreas. Since the neoplasm involved several organs, we propose that the condition was of multicentric origin. Gross lesions, histopathologic findings and the organs involved differed from a previously described case of lymphosarcoma in a raccoon.