Treatment of acute erythroleukaemia with high‐dose cytarabine in a cat with feline leukaemia virus infection

Abstract Erythroleukaemia is a malignant neoplasm of the erythroid lineage that rarely occurs in cats. It is associated with the feline leukaemia virus (FeLV), and owing to the poor prognosis, treatment is rarely reported. A 4‐year‐old female Korean domestic shorthair cat was presented with hyporexia, fever, lethargy, severe anaemia and rubricytosis. An FeLV antigen test was positive, but a subsequent polymerase chain reaction test was negative. Serum biochemistry analysis results were normal, except for slightly elevated alanine aminotransferase. The patient was tentatively diagnosed with acute erythroleukaemia, and single high‐dose (600 mg/m2) cytarabine chemotherapy was administered via constant rate infusion for 12 h a day for 5 days. After the first cytarabine administration, the clinical signs and anaemia improved, though no change was noted to other haematological parameters. The patient died of shock 16 days after the second cytarabine administration; the total survival time after diagnosis was 67 days. Post‐mortem cytological evaluation of bone marrow aspiration revealed that the myeloid/erythroid ratio was 0.49, the erythroid progenitor cells were 64% of all nucleated cells and the blast cells were 84% of the non‐erythroid cells. Histopathology images indicated that the spleen was diffusely expanded by atypical round cells, possibly erythroid precursors. This is the first case report on the prognosis and effects of high‐dose cytarabine chemotherapy for acute feline erythroleukaemia with FeLV infection. Although the clinical signs improved, the treatment was not effective. Further studies on erythroleukaemia chemotherapy protocols are required.