Proportion of mast cells in normal canine hepatic cytologic specimens: comparison of 2 staining methods.

BACKGROUND

Although the presence of mast cells is considered a normal finding in canine hepatic tissue, the normal proportion of these cells in cytologic specimens from normal livers was not previously established.

OBJECTIVES

The objective of this study was to determine the normal proportion of hepatic mast cells in cytologic specimens from normal canine liver by the use and comparison of the May-Grünwald-Giemsa and the Toluidine Blue staining methods.

METHODS

The cytologic specimens obtained from fine-needle aspirates of livers of 13 healthy dogs were investigated by counting of hepatocytes and mast cells per high-power field (HPF, x40 objective). The ratio of mast cells/100 hepatocytes was then compared between the 2 staining methods.

RESULTS

A median of 0.17 (range: 0-0.33) mast cells/100 hepatocytes and of 0.47 (range: 0-0.86) mast cells/100 hepatocytes was obtained with May-Grünwald-Giemsa and Toluidine Blue stains, respectively.

CONCLUSIONS

Toluidine Blue stain detects more hepatic mast cells than May-Grunwald-Giemsa in normal canine livers. With both stains, < 1% mast cells were detected in normal canine liver samples.