The accuracy of cytology in diagnosis and DNA analysis of canine mammary tumours.

Fine-needle aspirates from 84 spontaneous canine mammary tumours were used to assess the accuracy of this method in flow cytometric DNA analysis and cytological diagnosis. Defined samples from different tumour parts were analysed for histological diagnosis and DNA ploidy as a control. The DNA ploidy in cytology specimens and those obtained from the defined tumour samples, when testing for independence, was highly significant (P = 0.0001). The total accuracy of cytology was 79 per cent, with a sensitivity of 65 per cent and a specificity of 94 per cent. The results show the possibility of combining cytology and DNA analysis of fine-needle aspirates from canine mammary tumours. The method is suitable for preoperative diagnosis of canine mammary tumours as well as for measuring DNA ploidy, which makes it useful if DNA ploidy turns out to be of diagnostic and prognostic value in these tumours.