Acute myeloid leukemia (AML) is a myeloproliferative neoplasm that arises in the bone marrow. AML is associated with high morbidity and mortality. AML in cats has often been associated with infection by feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV). However, few patients have been reported to develop AML without FIV or FeLV infection. This abstract reports presentation, hematology, cytology, histopathology, and outcomes in retrovirus-negative cats diagnosed with AML.

Sixteen patients were diagnosed with AML based on bone marrow cytology, histology, or post mortem: 8 castrated males, 1 intact male, and 7 spayed females. Eleven cats were domestic shorthair, 1 domestic longhair, 1 Siamese, 1 Ragdoll, 1 Norwegian Forest, and 1 Egyptian Mau. Thirteen cats were anemic (median HCT 17% [7–37]) at presentation and 12 cats were thrombocytopenic (median PLT 54 x 10⁹ L [4–202]). Leukopenia (median WBC 3.5 x 10⁹ L [0.4–27.3]) consisting of neutropenia was present in 12 cats. Leukocytosis due to neutrophilia was present in 1 patient. Blast or atypical cells were identified on the blood smear in 14 patients, and red blood cell agglutination in 6 cats. Treatments included antibiotics, immunosuppression or chemotherapy with highly variable outcomes. Among the cats receiving immunosuppression 6 were euthanized within a week; 4 others lived 1, 4, 6, and 12 months, and one is alive after 1 year. Two cats receiving antibiotics were euthanized within 2 weeks. Three cats received chemotherapy, one lived 5 months and two are currently being treated. AML should be considered in retrovirus-negative cats with cytopenias.

Disclosures

No disclosures to report.