Comparison of nuclear morphometric parameters in cytologic smears and histologic sections of spontaneous canine tumors

Background — Nuclear morphometry may provide useful diagnostic and prognostic information for neoplasms in animals. Most available data have been obtained from histologic sections. Nuclear morphometry of cytologic smears may provide important preoperative information. Objectives — The goal of this study was to compare nuclear morphometric parameters in cytologic smears and histologic sections from spontaneous canine tumors. Methods — Mean nuclear area (MNA), mean nuclear perimeter (MNP), mean nuclear form factor (FF; nuclear perimeter2/4 nuclear area) and their respective SDs were assessed by image analysis of both hematoxylin and eosin–stained histologic sections and May-Grünwald-Giemsa–stained cytologic smears from the same case in 20 spontaneous canine tumors of different histogenesis.The above parameters were selected as being the best morphometric tools for measuring variation in shape and size in cells after neoplastic transformation. Data were compared by ANOVA with P<.01 considered significant. Results — There was a significant difference between histologic and cytologic specimens for MNA, MNP, and their SDs. Only the differences between FF and the SD of FF were not statistically significant. Conclusions — Only nuclear morphometric data related to nuclear shape and nuclear shape variability are comparable between histologic and cytologic specimens. Nuclear area and perimeter may be affected by the different fixation and smear preparation techniques used in histology and cytology.