Acute myelomonocytic leukaemia with short-term spontaneous remission in a cat

A 2-year-old, spayed female domestic shorthair cat was referred with a history of anorexia and depression of 1 week duration. On physical examination, the cat was lethargic and febrile, with splenomegaly, anisocoria and ulcerative stomatitis. A complete blood count (CBC) and a biochemistry profile showed leukocytosis, numerous blast cells in the peripheral blood, thrombocytopenia, hyperglobulinaemia and a positive test for feline leukaemia virus antigen. A diagnosis of acute myelomonocytic leukaemia was made on the basis of the results of bone marrow cytology, histopathology, and immunochemistry (CD3, CD79a, lysozyme, and myeloperoxidase) tests. Following an unexpected 1-month period of clinical and clinicopathological remission without chemotherapy, the cat relapsed and died 1 week later.