Diffuse Large B-Cell Lymphoma (DLBCL) in an Aged Raccoon (Procyon lotor)

SIMPLE SUMMARY: The monitoring of wildlife disease patterns is important because wild species represent the human–environment interface, making them useful sentinels for both human and animal health. We aimed to classify the lymphoid neoplasm detected during necropsy based on the topography, cell type, and immunophenotype of neoplastic lymphocytes in a captive raccoon. There is substantial evidence showing the histopathological similarities among many tumors, even in unconventional species, which may represent possible alterative models worthy of investigation. In our study, the successful use of immunohistochemistry with clinically relevant human and canine biomarkers allowed us to diagnose multicentric diffuse large B cell lymphoma in raccoons. ABSTRACT: A 15-years-old, captive, female raccoon (Procyon lotor) was necropsied after a one-week history of apathy and self-isolation. Gross changes consisted of the severe enlargement of the mesenteric lymph node; hepatosplenomegaly with multifocal to coalescing, white tan nodules in the spleen and liver,; and pale kidneys. Histologically, neoplastic CD79α-positive lymphocytes effaced the mesenteric lymph node and multifocally infiltrated the spleen, liver, and kidneys, and focally infiltrated the heart. Based on pathological and immunohistochemical findings, as well as the canine-adapted World Health Organization (WHO) diagnostic criteria, a diagnosis of diffuse large B-cell lymphoma (DLBCL) was made.