Determination of the number of mast cells in lymph node, bone marrow, and buffy coat cytologic specimens from dogs.

Cytologic samples of popliteal lymph node, proximal femoral bone marrow, and the buffy coat fraction of blood were obtained from 56 dogs. The number of mast cells on 1 slide of each sample was determined by microscopic examination. Eleven of 46 slides of lymph node aspirate contained mast cells (range, 1 to 16; mean, 6.4; median, 5 mast cells/slide). Fifty-one bone marrow aspirate slides were evaluated. Two of these contained a single mast cell. None of the 53 buffy coat smear slides examined contained any mast cells. These results indicated that in clinically normal dogs, a few to several mast cells may be encountered in smears of lymph node aspirate, mast cells are rare in smears of bone marrow aspirate, and mast cells are absent from smears of buffy coat.