508 Vet Pathol 39:4, 2002Brief Communications and Case Reports Vet Pathol 39:508–511 (2002) Hepatosplenic T-cell Lymphoma in a Mare

Abstract. A 21-year-old Dutch crossbred mare was presented with a 1-month history of weight loss and weakness. Clinical evaluation revealed severe anemia and thrombocytopenia with evidence of hepatic disease and muscular damage. Necropsy findings included diaphragmatic rupture with an extensive retroperitoneal hematoma and severe hepatosplenomegaly. Microscopic findings were characterized by hepatic sinusoidal and splenic red pulp infiltration by atypical CD3-positive lymphocytes. No other nodal or extranodal sites were affected. Hepatosplenic lymphoma with a probable T-cell origin was diagnosed based on gross and histologic findings. Key words: Hepatosplenic disease; horses; immunohistochemistry; lymphoma; phenotype; T cell. Lymphoma is considered the most frequent neoplasm of the equine hematopoietic system, with an incidence of 0.7– 3.2/100,000 horses.16,17 Equine lymphomas are currently grouped into four clinical–pathologic presentations involving primarily either lymph nodes (multicentric form) or extran-odal sites such as alimentary canal, skin, or thymus.18,23 The at PENNSYLVANIA STATE UNIV on September 19, 2016vet.sagepub.comDownloaded fro