Frequency and severity of mastocytemia in dogs with and without mast cell tumors: 120 cases (1995-1997)

Objective-To elucidate frequency of detection on blood smears and severity on quantitative buffy coat evaluation of mastocytemia between dogs without mast cell tumors (MCT) and dogs that had MCT, and to expand the list of dis eases associated with mastocytemia in dogs without MCT. Design-Retrospective study. Animals-94 dogs without MCT and 26 dogs with MCT. Procedure-Medical records of ail dogs with mast cells detected on blood or buffy coat smears during a 2-year period were reviewed. Dogs with mastocyte mia were grouped by disease into dogs with MCT and dogs without MCT. Twenty -five of the dogs without MCT that had mast cells detected on blood smears also had evaluations of buffy coat smears. Quantitative buffy coat results of the 25 dogs without MCT were compared with those of the 26 dogs with MCT . Results-95.5% of blood smears with mast cells detected during CBC determina tion were from dogs without MCT. For these dogs, diagnoses included inflamm atory disease (28.2%), regenerative anemia (27%), neoplasia other than MCT (25.9%), and trauma (11.8%). Dogs with MCT had a mean of 71.4 mast cells/bu ffy coat smear, whereas dogs without MCT had a mean of 276.2 mast cells/buf fy coat smear. The 2 highest counts of mast cells/buffy coat smear were for dogs without MCT. Conclusions and Clinical Relevance-On the basis of results of quantitative buffy coat evaluations, severity of mastocytemia in dogs without MCT often exceeds that detected during tumor staging in dogs with MCT. Random detecti on of mast cells in blood smears during CBC determination in dogs is usuall y not secondary to MCT.