Digital squamous cell carcinoma in dogs: epidemiological, histological, and immunohistochemical study.

Squamous cell carcinoma represents 47.4% of all malignant canine digital lesions, but despite its frequency, there are few published studies available. Pathology submission records of 154 cases and follow-up of 49 animals were analyzed. On the 49 cases, histological evaluation was performed of the differentiation degree, mitotic index, presence of emboli, and immunohistochemical expression of vimentin and E-cadherin. The mean (SD) age of affected animals was 10.2 (2.3) years; no sex predisposition was recorded. Beauceron and Briard were 2 new overrepresented breeds. Dark-haired animals comprised 97 of 105 (92%); 94 dogs of 125 (75.2%) belonged to large and giant breeds. The forelimb was affected twice more than the hind limb. Probable metastases were observed in 4 dogs; new tumor development was recorded in 11 of 49 (22.4%). Epidemiologic factors, histological grade, mitotic index, and expression of immunohistochemical markers seemed not to be related to the clinical outcome.