engleski

Mast cell tumor in dogs. Incidence and histopathological characterisation

ncidence of the mast cell tumors , their distribution according to sex, breed, age and localisation in Croatia is not established yet. Also, the statistical significance of the various histopathological parameters according to Patnaik's scheme, in the diagnostics of the tumor grade was not performed.Investigation analysed mast cell tumors histopathologicaly characterized at the Department of General Pathology and Pathological Morphology of the Veterinary Faculty Zagreb from January 1st 2002. to Dezember 31st 2006. Sex, age, breed, localisation and tumor grade of each animal with tumor was recorded. Statistical evaluation was performed using nonparametric chi square test with one or two sample. Each histopathological finding (localisation, growth, cellularity, size and shape of cells, cell borders, granules, shape and localisation of the nuclei, nucleolus, hyperchromasia, anizocytosis, kariomegaly, anozokaryosis, mitoses, eosinophilic infiltrate, colagenolysis, necrosis, hemorrhages, mineralisation and ulceration) was scored 0-no change, 1-mild, 2-moderate, 3-severe, and statistically compared with tumor grade. Normality of distribution was checked with Kolmogorov-Smirnova test and significance was calculated with unifactorial one-way ANOVA or Kruskal-Wallis variance analysis.In the analysed period, totally 1630 dog tumors were analysed, and mast cell tumors were found in 106 animals or in 6, 5 % of all cases. With statistically significant difference, this tumor was recorded in more cases in male dogs (63, 2% males, 36, 8% females). Average age was 6, 964 years in the range from six months old terier to 14 years old schnaucer. Boxers and retreivers were most frequent breeds, and localisation was mostly on legs. Grade I tumor was found in 15, 09%, grade II in 44, 34% and grade III in 28, 3% of animals. There were no significant correlation between tumor grade and age, breed, sex or localisation although male animals tend to have more often grade I and females grade III tumors. Considering the lesion scores, statistically significant differences were found in cell shape, number of nucleouli, anizocytosis, amizokariosys, kariomegalia, mitoses, necrosis, hemorrhages, cellularity, cell borders and collagenolysis.This findings differs from the literature data considering the sex risk and incidence. Incidence is usually higher than in our data, and all literature state that there is no sex risk considering mast cell tumors in dogs. The reason for this may be the overally higher number of male dogs kept as pets in Croatia, which influence our results. Considerig histopathological findings, this results showed that there is no uniform influence of the various parameters on tumor grade. This significantly changed parameters (higher scores in the more malignant mast cell tumor) should be evaluated more carefully during routine tumor analysis.

dogs; mast cell tumor; incidence; histopathological characterisation

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