Clinicopathological findings and results of bone marrow aspiration in dogs with cutaneous mast cell tumours: 157 cases (1999-2002).

Bone marrow aspiration for routine staging of canine cutaneous mast cell tumour is not consistently performed, and the overall incidence of bone marrow infiltration and predictive value of the complete blood count (CBC) is unknown. This study evaluated a series of 157 dogs presented for cutaneous mast cell tumours in which a CBC and bone marrow aspiration were performed. The incidence of bone marrow infiltration at initial staging was low at 2.8%, and 4.5% overall. Factors significantly associated with bone marrow infiltration included increased age, leucocytosis, anaemia, neutrophilia, monocytosis, eosinophilia, thrombocytopenia, being purebred and staging at the time of recurrent or progressive disease. Our study suggests that a bone marrow sample is not indicated for routine staging but maybe indicated for those dogs with mast cell tumours having either an abnormal haemogram (neutrophilia, monocytosis, eosinophilia, basophilia, anaemia and thrombocytopenia) or presenting for tumour regrowth, progression or new occurrence.