Utility of nuclear morphometry in the cytologic evaluation of canine cutaneous soft tissue sarcomas.

Cytopathologists lack reliable criteria to distinguish neoplastic from reactive spindle cells; however, with computer-based nuclear morphometry, it is now possible to more objectively and precisely quantify differences between selected populations of cells. Forty-four cutaneous soft tissue sarcomas and 5 cases of reactive spindle cell proliferations in the dog were morphometrically analyzed with regard to median and standard deviation (SD) of nuclear area, diameter (max, min, mean), radius (max, min), perimeter, and roundness. Overall, nuclei from reactive spindle cells were larger, with greater variation in nuclear size and shape. Significant differences (P < 0.05) were found for several nuclear parameters, including the median and SD of maximum diameter and radius, as well as the SD of roundness. No significant differences were found in nuclear parameters between soft tissue sarcomas divided by histologic grade, mitotic index, or tumor necrosis score. Analysis of the sources of variation indicated near-...