CASE REPORT: A CHRONIC B-CELL LEUKEMIA IN A EURASIAN OTTER (Lutra lutra)

Abstract

A 12-year-old, female, Eurasian otter (Lutra lutra) reared in Taipei zoo was submitted for necropsy due to sudden death without remarkable clinical history. Parameters of the latest hematology were all within normal limits. At necropsy, there were large amounts of abdominal effusion, diffuse splenohepatomegaly, generalized lymphadenopathy, consolidation of the lung, and bilateral enlargement of both adrenal glands. Histological examination revealed large numbers of small to medium-sized neoplastic lymphocytes disrupting the normal architectures of the spleen, liver, lymph nodes, lung, mesentery, and adrenal glands. Immunohistochemistry showed diffuse positivity of tumor cells for CD79a but negativity for CD3. There were scattered positive signals for Ki-67 mainly in the spleen in sites of extramedullary hematopoiesis and lymph nodes. The neoplasm was considered a chronic lymphocytic leukemia of B-cell origin.