Medical records of 117 dogs with digit masses were reviewed. Of 124 digit masses, 76 (61%) were malignant neoplasms, 25 (20%) were benign neoplasms, and 23 (19%) were pyogranulomatous inflammation. Of 29 digits with radiographic evidence of bone lysis, 24 (83%) were affected by malignant masses, whereas only 5 of 29 (17%) digits with radiographic evidence of bone lysis were affected by benign or pyogranulomatous masses. Only 1 of 19 (5%) dogs with melanoma had radiographic evidence of lysis, but 20 of 25 (80%) dogs with squamous cell carcinoma had radiographic evidence of bone lysis. Thoracic radiographs of 95 dogs were available. Six of 19 (32%) dogs with melanoma had radiographic evidence of pulmonary metastasis at the time of diagnosis, whereas 3 of 24 (13%) dogs with squamous cell carcinoma had radiographic evidence of pulmonary metastasis at the time of diagnosis. Twenty-nine digit neoplasms were squamous cell carcinoma, and 19 of 29 (66%) arose from the subungual epithelium. Of 19 dogs with squamous cell carcinoma originating from the subungual epithelium, 18 (95%) survived for at least 1 year, whereas only 6 of 10 (60%) dogs with squamous cell carcinoma originating in other parts of the digit survived for at least 1 year. Furthermore, of 19 dogs with squamous cell carcinoma originating from the subungual epithelium, 14 (74%) survived at least 2 years, whereas only 4 of 9 (44%) dogs with squamous cell carcinoma originating in other parts of the digit survived for 2 years. Dogs with melanoma of the digits had a median survival time of 12 months, with 10 of 24 (42%) alive at 1 year and 3 of 23 (13%) alive at 2 years.(ABSTRACT TRUNCATED AT 250 WORDS)