Simple SummaryIn schnauzers, a breed predisposition to squamous cell carcinoma of the digit (dSCC) is well known. In terms of the breed, the variants of giant (GSs), standard (SSs), and miniature schnauzers (MSs), as well as the traits of body size and/or genetic background may have an impact on tumour occurrence and prognosis. We, therefore, conducted a retrospective analysis of the pathological findings of 478 digital SCCs from 417 schnauzers (227 GSs, 174 SSs, and 16 MSs). The results showed that MSs were older when digital SCC appeared, and lesions were mostly (90%) nodular. A gender predisposition for male GSs was identified (p< 0.05). In GSs, nodular lesions were larger than in MSs and SSs. In all breed variants, SCC was mostly diagnosed at the forelimbs, especially at digits 1, 2, and 5. In contrast, at the hindlimbs, the affected toes differed between GSs and SSs. Multiple dSCCs were more common in SSs than in GSs. If dSCC was the cause of death, the survival time was shorter than in dogs dying from other diseases. Metastases occurred in 20% of the cases and led to a significantly shorter survival time in GSs and SSs. The results showed various differences in the dSCC depending on the size variant of the schnauzer.AbstractIn schnauzers, a breed predisposition to squamous cell carcinoma of the digit (dSCC) is well known. The aim of this study was to compare the clinical and macroscopic findings of dSCCs in giant (GSs), standard (SSs), and miniature schnauzers (MSs). Methods: Pathology reports of 478 dSCCs from 417 schnauzers (227 GSs, 174 SSs, and 16 MSs) were retrospectively evaluated. Results: The MSs were older than the SSs and GSs (p≤ 0.01). The male GSs were predisposed to dSCC (p< 0.05). In the GSs, the nodular dSCCs were larger than in the MSs (p≤ 0.05) and SSs (p≤ 0.001). The digital SCCs were mostly diagnosed at the forelimbs, especially at digits 1, 2, and 5. At the hindlimbs, the affected toes differed between the GSs and SSs. Multiple dSCCs were more common in SSs than in GSs (p= 0.003). If dSCC was the cause of death, the survival time was shorter than in dogs dying from other diseases (p= 0.004). Metastases occurred in 20% of the cases and led to a significantly shorter survival time in both the GSs and SSs (p< 0.001). Conclusions: The results showed various differences in the dSCC depending on the size variant of the schnauzer.