Association of histologic tumor characteristics and size of surgical margins with clinical outcome after surgical removal of cutaneous mast cell tumors in dogs

Objective—To evaluate the relationship between width and depth of surgical margins, amount of edema within and around the tumor, and degree of demarcation between the tumor and surrounding tissues with the clinical outcome following surgical removal of cutaneous mast cell tumors (cMCTs) in dogs. Design—Retrospective cohort study. Animals—100 dogs with 115 resectable cMCTs. Procedures—Information about the dogs' clinical outcomes following cMCT removal was obtained from primary care veterinarians. Histologic sections of excised tumors were assessed retrospectively for tumor grade and measurement of the narrowest lateral and deep margins of nonneoplastic tissue excised with the tumors; edema within the tumor and surrounding tissues was assessed as minimal, moderate, or severe. Tumors were classified as poorly, moderately, or well demarcated on the basis of the degree of mast cell infiltration into the adjoining connective tissue. Results—Following tumor excision (with no additional postsurgery treatment), 9...