Paraneoplastic Hypereosinophilia in a Dog with Intestinal T-Cell Lymphoma

Paraneoplastic hypereosinophilia, characterized by the infiltration of eosinophils into systemic organs, has rarely been reported in dogs with intestinal lymphoma. A 12-year-old spayed female Maltese with eosinophilia in the peripheral blood and ascites was found to have muscular layer thickening in the small intestine. Histologically, there was transmural infiltration of small to intermediate sized neoplastic lymphocytes that were immunohistochemically CD3-/CD79a-. PCR for antigen receptor rearrangement demonstrated clonal T cell receptor gene population. A moderate number of eosinophils were present along with neoplastic lymphocytes in the small intestine, and eosinophil infiltration was also noted in the abdominal lymph nodes and spleen. The present case reports intestinal T-cell lymphoma with generalized paraneoplastic hypereosinophilia. Clini-cians should be aware that hypereosinophilia can be found in the organs, body cavity fluid, and peripheral blood of dogs with intestinal lymphoma.