Breed predisposition in schnauzers for certain neoplasms is well documented. However, this does not seem to apply to all size variants. The aim of the study was to evaluate the frequency of different neoplasms in giant (GS), standard (SS) and miniature schnauzers (MS) submitted to LABOKLIN GmbH & Co. KG (2016-2019) for routine diagnostics. To this end, 1,321 histopathological samples from schnauzers (644 GS, 390 SS, 287 MS) were evaluated. The proportion of the different neoplasms varied depending on the size. GS had more melanocytomas and/or melanomas than MS (p=0.004 and p=0.037) or SS (p=0.023 and p<0.001). The frequency of squamous cell carcinoma (SCC) in GS and SS was significantly higher than in MS (p<0.001), while the latter had a higher proportion of mammary tumors than both SS (p=0.001) and GS (p<0.001). Not surprisingly, over 93% of the diagnosed SCCs were located in the digit (DSCC), mostly represented by GS (55%) and SS (42.5%), and rarely MS (2.5%). Out of these, DSCC from 26 GS and 8 SS were graded according to adapted system from Nagamine et al. 1. Distribution of grades I, II and III were similar: GS: 12, 10, 4 and SS: 3, 4, 1, respectively. These significant differences, and specially when talking about DSCC, may reflect an underlying genetic predisposition or protection, driven by the subtle different genetic background because of intensive breeding and selection. Further studies are needed to confirm this.
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