title: Diagnosis and treatment of chronic T-lymphocytic leukemia in a spotted hyena (Crocuta crocuta).
abstract: Physical examination of an asymptomatic 20-yr-old intact female spotted hyena (Crocuta crocuta) revealed a midabdominal mass. A complete blood count (CBC) revealed peripheral lymphocytosis. Abdominal ultrasonography and laparoscopy confirmed severe splenomegaly. Cytologic examination of a bone-marrow core and histologic examination of spleen and liver biopsy samples revealed neoplastic small lymphocytes. Immunohistochemical staining of liver and spleen samples with the use of leukocyte-specific monoclonal antibodies showed that the neoplastic lymphocytes were immunoreactive to T-lymphocyte CD3 receptor and immunonegative to B-lymphocyte CD79a receptor. The morphology and distribution of neoplastic T-lymphocytes within the spleen, liver, peripheral blood, and bone marrow was most consistent with chronic T-lymphocytic leukemia. Treatment with chlorambucil and prednisone effectively decreased the lymphocyte count, but was associated with thrombocytopenia, which resolved after chlorambucil treatment was temporarily discontinued. Chemotherapy was resumed with a single dose of L-asparaginase, followed by a lower dosage of chlorambucil and continued prednisone. Two years after initial diagnosis, the hyena developed a hemoabdomen and was euthanized. Neoplastic T-lymphocytes were present in spleen, liver, visceral and peripheral lymph nodes, lungs, heart, kidney, adrenal glands, mesentery, intestines, pancreas, brain, and bone marrow.
authors.affiliation: Zoological Medicine Service, School of Veterinary Medicine, University of California, Davis, California 95616, USA. cora.singleton@lacity.org
authors.forename: Cora L
authors.initials: CL
authors.lastname: Singleton
authors.forename: Raymund F
authors.initials: RF
authors.lastname: Wack
authors.forename: Tanja S
authors.initials: TS
authors.lastname: Zabka
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kent
authors.forename: R Scott
authors.initials: RS
authors.lastname: Larsen
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D017809:Fatal Outcome; D005260:Female; D045968:Hyaenidae; D015458:Leukemia, T-Cell / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D009362:Neoplasm Metastasis; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents